First, I really dislike calling the things Wizards puts out "adventure paths". A path is made up of many steps – Paizo now does them mostly in 3-volume installments either going from 1-10 or 11-20, and used to do them in 6-volume ones. I prefer "campaign-length adventures" or just "campaigns."Or: why does wotc make paths instead of sandboxes?
Second, because sandboxes are very poorly suited to publishing. A sandbox ought to have much more material in it than actually gets used (otherwise it's just a regular adventure where you can go to the nodes in different orders), which makes it pretty wasteful. It also puts a pretty big burden on the GM, because there are lots of different things to keep track of. In a linear campaign, it's enough to have a vague overview of the whole thing and focus on the next step, and that's a lot easier.
D&D is also fairly unsuited to sandboxes because of power escalation. IME, they work better in flatter systems.
Thing is, 5-6 sessions per level means you need about 50 sessions to go from level 1 to 10. Even if you're playing weekly, that's a year of gaming. It is rare for a campaign to run that long.I think 5 to 6 sessions per level is probably about the right rate of advancement.
So yes.
But I think I'm in the minority.
The realities of publishing is that if a 256-page book would cost $60, that doesn't mean that a 64-page book would cost $15. It'd be more like $40, when you consider the lower print run and other issues.Yeah Morrus, but, I have to buy the whole book just to find out there are only 2 or 3 adventures from the anthology l would actually run. I'm getting sick of that.
Paizo's APs these days cover 10 levels over 3 volumes. Each of those volumes is 96 pages, with about 64 pages being the actual adventure and the rest being supporting material (e.g. if the adventure takes place in a city, part of those additional 32 pages would be a gazetteer of the city, and you'd also have some new creatures and magic items and such, some of which would show up in the actual adventure). And in my experience, that's squeezing it in tight – you'd probably need about 96 pages of actual adventure for each installment to give it time to breathe.One of the problems with adventure paths is they would be 900 pages long and cost $200 (USD) of they actually had the experience in the needed for leveling as advertised. l am beginning to see this as a weakness of the adventure path format that we overcome with Milestone advancement. (Perhaps, I am just speculating)