According to a Wizards survey, most people run their games using homebrew. Now this can mean anything from using an established setting but giving it your own stamp, or using a completely made up world.
Now Wizards always claimed they were using the surveys to give people what they want but it seems what people want doesn't align with that Wizards wants. When people say they run most of their games using homebrew then you would think they would be jumping to make more regional books, non setting books, and more DM's aids. I think this has been a product of the surveys all along but that's another topic.
So Wizards, we have told you what we want and how we run our games and yet you still try and shove AP's down our throats.
Why?
Somewhere down thread this veered into a slightly different area, but I'd like to respond to the original post.
What most people report they play and what people will buy are two different things.
Homebrew campaigns seem to be one of two different types - either they buy everything and pick and choose, or they buy nothing because all they need are the core books and everything else is their home-brew campaign. I would guess that most of them are the former - they don't buy a lot of published materials.
From a sales standpoint, they learned that more isn't necessarily better. In addition, they have indicated that they aren't interested in just republishing the same material that has been published before. For long-time Forgotten Realms players, for example, a lot of the text in the 3/3.5e supplements was lifted directly from earlier 1e/2e sources. Actually, a lot of the 2e stuff was cut and paste from the 1e supplements.
The 3.5e FR books for example, have all of the regional information and lore that most people would need. Not that much would be updated for a 5e campaign, and they are already covering those aspects in the APs. I have purchased all of them, because I find material in each one I can use in my specific FR campaign. I don't run the AP, but sometimes pull out parts for other adventures.
Yes, there are other aspects, like the spells, magic items, races, and classes (particularly in the 3/3.5e material), but they are taking a different approach to a lot of that.
Volo's Guide to Monsters is a nice approach to update the concept of the Monster Manual instead of just releasing MMII, MMIII, etc. I hope we'll see a similar concept for spells and magic items.
As for the Adventure Paths, they have settled on a new approach that combines the old regional sourcebooks with a multi-part adventure. In the past, many of these might have been separate products made to work together. The problem is that with publishing costs the way they are, combined with the likely number of sales, one large book is more viable than several smaller ones.
I certainly don't think they are "shoving them down our throats." They are sticking with the approach right now because it's working. The vocal folks on forums like this aren't the target audience for the adventure paths. The target audience is the more casual gamer. Those that have the core books and a group of friends, and want to pick up the new adventure and play. The aren't interested in building their own homebrew campaign world. They probably aren't interested in a campaign the way I would approach it at all.
My campaigns are character focused with players playing the same characters for years. Adventure paths are designed to go from 1st to 15th level in a single story arc, and you need to start new characters for the next campaign. The average life-span for those characters is probably 3 to 6 months of play time.
So "we" might have answered the surveys and given them some idea of what people are looking for, but "we" are a very small part of the gaming community. The paying community by all accounts is growing, and is quite happy with the approach so far.
Providing material to the homebrew crowd has always been difficult. I think the DMsGuild services that crowd very well, though.
Volo's Guide to Monsters seems like a hit as well. From what I can see they will keep building off of their successes in an intelligent way. From all continuing reports I've seen D&D is enjoying not only a renaissance, but a sustained surge in sales. I strongly suspect that their new publishing approach along with their approach to bringing different media into a unified sales cycle has also increased profitability quite a bit, not just sales.
In the business world, you survey your customers to see what they are looking for, and you measure your success to that response in sales and profitability. Best I can tell, they are a great success in that regard.