FWIW I don't think Valve is hurting for money enough to make a decision like this for that reason. I assume they honestly want to make their customers happier, but whether this somehow achieves that or not is another question entirely.
I agree. Money is a result of audience, satisfaction and engagement.
Pay to send, the objective should be decreases the number of game submissions.
To, at least, not become a platform of "zombie apps" like Google Playhttps://thenextweb.com/google/2017/02/08/millions-apps-soon-purged-google-play-store/
However, it's as they said above, a "standard quality" can solve the problem of "zombie games". But, others indie games that no "buy success with ads", also end up being considered zombies, scrap, waste.
The result of this is the developers will prefer create the "standard games" that they want advertise in front pages.
With this, all return again to the problem of clones, similar games, etc. The games only become "quality zombies".