I’m not convinced there’s a real problem here to solve. The floodgates have opened, yes.
A lot of people seem to think that means they’ll see every bad game that’s been released on Steam so far. But, for the most part, those games don’t get in the way. They’re invisible to the bulk of Steam’s viewers, because (beyond their initial impressions) they’re not seen by those viewers.
There would be a problem if great games weren’t being surfaced — but again, it’s not entirely clear this is the case. People are certainly buying more games on average each year — so presumably Steam is doing a better job of presenting them with things they’d like to play.
So Steam is growing the market, helping more developers make more money, and helping players find more content they’d like to spend money on. Where’s the problem?