This is a really important one because a lot of games nowadays are made under the expectation that they will be shut down as soon as they are slightly unprofitable. It doesn't have to be this way, and if you need proof look at the decade old games that still keep their servers up even though they only have like 20 players.

Oh, I believe you that it's there. My point is that the cast majority of users never see those games because they are generally buried by Steam's algorithms.

One thing that I've noticed is that Steam seems very sensitive to what you've been viewing recently. When I was actively searching asset flips to report I saw a lot of junk games on the featured page. After I stopped for a few weeks and focused only on the games that I liked, the main page got a lot better. Now I almost never see a junk game unless I actively search for it.

This tells me that overall the algorithm seems to be working. YMMV, but if you are seeing a lot of horrible games, I suggest you take a break from policing for a month or two and you'll start to notice that the featured page should change. It won't be perfect, of course, but IMO Steam's algorithms are better at pushing up quality content than other totally open marketplaces (like the android store, or itch.io, for example).

Maybe I'm misunderstanding, but did you basically use the discovery queue for 40k games?

If so, I'm not surprised about the statistics that you posted, and IMO it shows that Steam is actually working properly. Let me explain:

From what I understand, the discovery queue doesn't feature games that you have already wishlisted or games that you have viewed recently. The first 15k games you wishlisted at a rate of 1/10 games, which is not bad in my opinion. After that it gets progressively worse, but that is because the Steam algorithm basically has to start scraping the bottom of the barrel because it is biased towards items that it hasn't already showed you, and it already showed you 15k items that it thought you'd like.

Perhaps your point is that the cruddy games shouldn't be on Steam at all, but at least it seems like the Steam algorithm is good at hiding stuff you don't like until you've viewed 15k items.

Also, I agree with you about tags, but those mostly seem to be user-driven.