“ We should be seeing 10,000 Tetris clones on Steam.”

Steam used to have a vetting process. Nowadays, they'll let you put basically anything on there, unless it's illegal or (de facto) it causes enough bad publicity that you're not worth the bother of dealing with. I believe there is a one-off fee to keep out the spammers and malware authors, but that's about it.

Of course, Steam is also flooded with shovelware, and has been since they adopted the above policy (well before the AI boom), so it's not a useful metric for this anyway. Most people can't see a lot of this shovelware, because Steam hides porn games by default, but it definitely exists.

(The above is not meant to imply that *all* porn games are shovelware. Quite a lot of shovelware is porn, however, because some users will happily pay a few dollars for sexualized images wrapped in a thin layer of gameplay, even though they would not pay for either in isolation. Go figure.)