Ruin Explorer
Legend
I don't see it as conservative, I believe it is simply good business. 5e has focused on what will sell in sufficient numbers, and so far it is working.
The end result is still a conservative set of settings being actually delivered to the gaming public. It may well have been "good business", but that end result is still there.
As I said, I have some expectation that this will change. When 5E launched I think WotC and Hasbro feared D&D might be "on the way out", but the exact opposite has happened (thanks in large part to Critical Role and various cultural changes that are causing D&D to kind of "have it's moment", but also thanks to 5E's accessible design). As 5E has been so successful, I think what was previously risky is now pretty low-risk. With a few million D&D players, 100k copies might have been a significant hurdle for a setting-book to clear. With tens of millions and growing? I think it'd be a lot easier to clear that.
We'll see, I guess. I also think there's less parasitism now from settings, because people buy them for different reasons. In 2E, you bought a setting typically for one of two reasons:
1) You intended to run it.
2) You were some kind of completist. And being a completist wasn't that common back then.
Nowadays, tons of people are completists or collectors, and want everything, and lots of people buy stuff just to read and get ideas from (which was definitely less true in the '90s), and further lots of people buy a book just to grab a few subclasses and races and a couple of Feats. So having a whole bunch of settings is less likely to cause other settings to not sell, now. You just need them all to have some appealing material, and to make people aware that they exist.
Again, though, when you talk about 5e being "conservative" for settings, that's only really true if we focus on WotC. Outside of WotC though, 5e is rapidly approaching 2e for number of settings and is quite possibly second only to 3e if we include 3rd party products.
This seems like an unrealistic position to me. It's extremely clear that the percentage of D&D players who use 3PP settings is pretty tiny, and the main issue is a simple lack of awareness of their existence. Just ask about a 3PP setting on the 5E subreddit (which is very very busy and full of younger players - teens to early thirties mostly), and see how many people have even heard of it. Typically it's few to none, unless it's Exandria. People often express interest after hearing about something, but the awareness isn't there.
The awareness of long-ago 2E products is actually way higher. Loads of people know about Planescape, because of the game, and because people like Mercer mention it a lot. Inexplicably huge numbers of people know about Spelljammer, I just don't even know how, but they do (though they typically know very few details beyond that it's D&D in fantasy space). Dark Sun is particularly well-known, and part of that is clearly because it had a release in 4E. And pretty much everyone knows of all the current WotC settings, even if they don't own them.
Awareness is everything. DMs Guild clearly isn't really penetrating that market, not with settings, anyway.