First off, xp for that chart - that's amazing! I think I might just steal this idea and take it to our game tonight, where we've been over ten years busy in enmeshing ourselves in a plot that seems to have neither end nor beginning.
And now, back into the trenches...
As a player: to make choices that will express one's character and shape the outcome of whatever it is that is at stake in play. As a GM: to work with the players to establish whatever it is that is at stake in play, and then push the players (and thereby their PCs) in respect of it.
Cool. This could in theory happen in any game, however, though it needs the right kind of players (who both seek and enjoy such high-drama situations) and DM (willing and able to facilitate such).
As for myself, I'm more interested in pushing the PCs rather than stressing the players; who are in theory just here for a good time (as am I).
Some people would rather have outcomes be determined by action resolution rather than dictated by the GM's hitherto-unrevealed and unilateral framing. I don't see how that is so hard to understand.
Who do you think disagrees with this? Obviously if there is no shop, then no shop can be found.
What we're discussing is how it might be established, as part of the preparation for and play of a RPG, that there is or isn't a shop.
And the mechanics for determining such, yes.
You have participated extensively in the other worldbuilding thread. In that thread you've read the account of the bazaar- and-feather scene; and taken part in a lot of discussions about it.
Now recall how you and some other posters have said that you would handle it - include how you have been critical of the idea of opening the game with the PCs at the bazaar and an angel feather being offered for sale.
The fact that the technique is something you're critical of seems to suggest that it is not the same as what is involved in worldbuilding.
Assuming - and please correct me if I'm wrong - that the bazaar example is typical, my criticisms of it lie in how anything leading up to that point is essentially skipped over, not least of which is an opportunity for the party to meet and get to know each other. Also, framing it such that the PC or party have to explore the town a bit before finding the feather merchant gives you a chance to tell them - yes, tell them

- what the town's all about, so as to better inform their later decisions, approaches, and actions.
If the orc kills the PC, and the GM has decided ahead of tiem that this is what will happen, that mode of decision-making is irrelevant to the here-and-now result. Nevertheless, many RPGers think it matters to the play of the game whether the combat is resolved via the standard mechanics, or by the GM deciding the outcome in advance.
Absolutely. The three (or four) "pillars" of the game work differently and thus are probably best served by using different mechanics.
Combat has more or less robust mechanics in pretty much all RPGs.
Exploration mechanics are a more open question...certainly 1e D&D and its ilk have the mechanics for small-scale dungeon exploration nailed down; but wilderness or city or space exploration mechanics are kind of all over the place, and there's a case to be made here that less is more. In any case, though, trying to make these mechanics work the same as combat is a square peg/round hole situation.
Social mechanics are covered in widely-varying quality by some game systems but not all, and here IMO less is certainly more no matter what. Matching these to combat is more like trying to put a square peg into something that has no hole at all.
The fourth "pillar" - downtime - really doesn't have or need much by way of action-level mechanics; more broad-based stuff like training, stronghold building, spell research etc. is either covered by the game system in use or can be handled case by case.
Action declarations aren't normally made on a whim - they pertain to the play of the game.
But if the players thing that the presence of a sage is plausible (and if they didn't, they wouldn't have their PCs try and find one), then that seems to settle the question of verisimilitude. Doesn't it?
It does...though part of the fun of playing is to be able to try the implausible.
You know - thinking about it, that's perhaps part of where story-now and I drift apart. As a player, I want to (and will!) try the implausible or impossible or just plain absurd now and then just for fun. But from what I can tell story-now (and I can't think of a better phrasing but this isn't perfect) takes itself too seriously for this sort of thing. High drama and high tension isn't often the stuff laughs are made of, and I'm in it for the laughs and entertainment most of the time.
Given that there are no shortage of players who prefer APs to "story now", I don't think that published/shared settings are under any sort of threat!
Given that it is central to "story now" that there is no "the story", it doesn't naturally lend itself to tournament/convention-type play, although I have played in convention games that approximate to it: normally the first session is used for the players to establish their feel for the PCs while the GM sets the scene; and the second session is the crunch.
I wasn't thinking so much of tournament or convention play, but of ongoing RPGA or AL-type play where you can establish your character during the weekly game at your FLGS then take said character to another game at a different store and drop it in, then take it to a convention and drop it into a game there, then return to your FLGS and keep the same character going; with all of these contributing to the character's continuing growth and development.
Personally this style of play isn't for me, but I recognize its significance as a major means of both attracting new players (and DMs) to the hobby and keeping them engaged once in; and thus I maintain that any RPG that wants to move beyond niche-within-the-hobby status kinda needs to set this up.
If this is not already obvious - for instance, if the game is "generic fantasy" then the answer to the questions about transport are horses, carts/wagons, and, if a port town, boats/ships - then if it is just colour someone at the table can make something up, and if it matters then checks can be declared and resolved.
If it's a major city in a magical world "teleport" may also be a transport answer.
But rather than going through all the checks-resolutions, isn't it both easier and quicker just to tell us up front what we know about the place, at least on an overview level? It could be as simple as:
"The campaign starts in Karnos on a warm sunny Midsummers' Day; each of you in your backgrounds has given your rationale for being in town. Karnos is a busy seaport town on the south coast of a region known as Decast, surrounded by gentle farmland to the north, east and west and with a good harbour to the south leading to open water. Major trade routes lead west and north. Its resident population is about 5000, with easily about another 1000 transients - mostly crew from the many tall ships docked or anchored here - in town much of the time. The town is mostly safe except for the "docklands", a few areas of dark alleys and shady characters near the waterfront; elsewhere the local constabulary - backed if needed by Count Vertuin's (the local ruler) strong militia - enforce order, sometimes with a heavy hand. As it's a port town people of nearly all races and cultures can easily be found, as can temples to most major faiths and pantheons; the resident population is mostly Human with a smattering of Hobbits and Part-Elves. By day the streets are often full, as are the many taverns, pubs and inns; at night the sound of revelry often echoes between the buildings until the wee hours; there is no formal curfew. Gear and equipment both mundane and exotic of almost any kind and size is available here; particularly at the twice-weekly markets in Dorian Plaza, the town's central square...and today is a market day."
There. How long did that take to narrate? Two minutes, tops; probably less, and not a single die was rolled. And now your players have a much stronger sense of atmosphere and knowledge of their surroundings than they otherwise would have (and which matches that of their PCs, even better!) to inform their decisions and actions; and from here you can either a) frame them straight into the market or their inn or a common meeting point or wherever or b) ask them individually what they are doing today...someone looking for exotic gear, for example, might head for the market.
Happy as I am to be flattered, frankly I think you're exaggerating in both respects. Keeping track of the events of play is not that hard; and to the extent that it is, I don't think worldbuilding GMs are going to do any better a job of it.
I guess my point is that worldbuilding DM's don't have to do as much of it during play, as the background stuff has already been done.
And this matters to me. I can't write and talk/listen at the same time (and know very few if any people who can), so the less in-session writing I have to do the better; because every minute I spend writing is a minute not spent talking or listening - and if I'm not talking or listening quite often that means things quickly grind to a halt...which kinda defeats the purpose.
I've attached the chart that one of my players maintained for our RM OA game, in pretty much its final state (after about 10 years of play).
As said above, this is one hell of a chart!
Lanefan