Steam and other digital storefronts should only allow professional developers to sell games

Perhaps you’ve missed it - I agree that Steam Direct barrier should have been much higher than what it is. But that has nothing to do with developers being professional or not.

Anyway, as Steam is getting flooded and discovery there is zero, the same money, that could have been spent for entry barrier, will be just added to marketing spend outside of Steam. So steam just stop being a marketing platform, not a big deal for anyone who already knows how to advertise your game. My only gripe with this is that you basically need publishers again, if you want a trouble free press coverage for your game and focus on development side instead.