The "you" in my post was being used in the impersonal sense (ie one doesn't answer the question of what money is for in the context of gameplay by producing a mediaeval price guide, which in any event the game includes.) A price list isn't advice on gameplay.
It's not? If the question is how can characters use their gold, a list of items with prices certainly seems to be advice on exactly that. It's limited advice, and depending on the list, may not be as broad as many would like, but it does address the concern to some extent.
But I think that this is one of the areas that touches upon what Mearls said. Here are the relevant bits below:
3.5 and 4 were very much driven by an anxiety about controlling the experience of the game, leaving as little as possible to chance. They aimed for consistency of play from campaign to campaign, and table to table. The fear was that an obnoxious player or DM would ruin the game, and that would drive people away from it. The thinking was that if we made things as procedural as possible, people would just follow the rules and have fun regardless of who they played with.
The downside to this approach is that the rules became comprehensive to a fault. The game’s rules bloated, as they sought to resolve many if not all questions that arise in play with the game text.
The intended design goal of 5E goes against the above. They don't want rules for everything. They don't want every group to play the game the same way. I think this is a conscious decision on their part.
With 5th, we assumed that the DM was there to have a good time, put on an engaging performance, and keep the group interested, excited, and happy. It’s a huge change, because we no longer expect you to turn to the book for an answer. We expect the DM to do that.
They expect the DM to have input on the game and how it works. And I think this also applies to the players, by implication. Come up with an idea...."Hey I bought some fancy clothes...can I gain advantage when I try to persuade the duke to help us?" and bring it to your DM rather then to the rule book.
This is the design choice they made. And this is what I like.
Could they have come up with rules for wardrobe and the impact it has on Persuasion or other social checks? Sure. Could they have come up with rules for how to build strongholds? Sure.
But they realize the importance of these things will vary from table to table. So they've left such things up to a specific group to decide.
You are correct that I can import advice on gameplay from other games into 5e - but that's not a super-strong defence of 5e's design, I don't think, especially as some advice will probably contradict how 5e is meant to play.
This is why I don't think there will be any convincing you. I think it's a key aspect to the design. Not feeling the need to spend time and space around a bunch of areas of the game whose importance will vary drastically from game to game and committing a bunch of mechanics to those areas ahead of time. Especially not when rather than spend that time and effort ahead of time, the player and DM can spend two minutes at the table and come up with something just as useful.
It seems to me based on your comments here, and in other conversations, that you want all mechanics to be determined ahead of time so that the players and DM have this established understanding of exactly what's possible and what works and how ahead of time. There's no judgment needed on the DM's part.
I actually like there to be such judgment. I don't see relying on the judgment of participants in the game to help make decisions about how to play to be lazy design. In fact, I consider it one of 5E's strongest elements.
This doesn't speak to my point, which is what is the gameplay purpose of imagining my PC spending money on those things?
If the answer is just because it's fun to imagine it - ie the expenditure is colour and nothing more - then maybe the book could come out and say so: the goal of playing a game in which you must succeed at wargame-like challenges to have your PC collect gold from a dungeon is to then imagine your PC spending that gold on whatever you want to.
It doesn't speak to your point because the answer will likely be different for everyone.
My game is not exactly the style you assume above, but my players' characters have indeed accumulated some money through play. They've used that money for a variety of things....most of which are more narrative than mechanical. They've established a trading company and they've needed funds for political purposes. There is upkeep involved in that, and a whole bevy of NPCs to pay for, and further investments related to the busines. One PC used the funds to establish a temple. Another used money to help in his search for his family. There has been a bit of magic item purchasing, as well, but not on a large scale.
For others, a lot of this would be boring and unnecessary. I don't think that the designers needed to provide all this to me ahead of time. My players and I can do that.
The same can be said of a Diablo-esque dungeoncrawl where the accumulation of wealth serves only to get better items, so that you can penetrate further into the dungeon, so that you can get more money, so you can get better items....and so on. For players of a game where this is the desired approach, how difficult is it to come up with a price guide for magic items?
So I don't think the fact that the designers know that different people will play differently, and consider some areas of the game more important than others, is a blindspot on their part. I think they're very aware of this, and considered it strongly in their approach. I think they came to the specific design decisions they came to with this in mind, in service of this design approach.
