I would be really disappointed if they upped the publishing fee simply because a lot of games I own on steam may not have ultimately been published, namely...
Unreal World, Curious Expedition, Sunless Sea, NEO Scavenger, etc. Each of these games could have just as easily been mobile exclusives.
To solve the problem of complete crap making it onto steam, Steam just needs to filter out poorly rated games more aggressively. I'm constantly getting complete garbage recommended to me... I don't care that crap games exist, I just can't stand that Steam still recommends abandoned early access title that have overwhelmingly negative reviews.
I'm working on a sports simulation that I intended to release on steam in the future, but damn $5,000 is a big hit to take. I've been working on this game for years for fun, but having to shell out $5k to see it released on Steam is not something I planned for.