I suppose that's true, and maybe it's not fair of me to think that way. I'm just tired of ideas being tossed because they can't meet WotC's arbitrary 70%, and complaints about multiclassing interactions are pretty common ones in response to UA. The single level MC issue comes up around here a lot.
For me, I agree with 70% methodology − even when there are certain results that I like less.
It helps keep most of 5e popular and useful.
It also helps prevent the edition from accumulating low-quality bloat.
By the way, the experimental UAs remain, even if they failed the 70% test. So there is still some quasi-official niche products already available. Personally, I am happy with the UA Modern, for example.
I am satisfied with DMsGuild being the go-to place for experimental niches.
That said, I find it difficult to navigate and to peruse DMsGuild content. So, even when it is there, it is hard for me to know where to look for high quality stuff that might interest me.
If I was in a physical bookstore, I would peruse the books (while drinking coffee) and decide if I want to purchase it. But that kind of freedom is more restrained in the DMsGuild setup, where there is only a predetermined glimpse, such as a table of contents, or a passage that might not be the part that I want to look more closely at. Here, I am unsure of a solution. Maybe each account can peruse a certain number of books per week, month, or year? Maybe pay money to refresh a perusal? Anyway, it would help me to look at the high quality costly offerings.
Of course, there is much high quality in DMsGuild that is pay-what-you-want! Here, navigation to find it is the main challenge.