How would you realistically go about this though?Personally, part of a problem to me, is that all of these games are advertised as being released on Steam, Valve dealing with this BS would be enough for me. If the game is announced as EGS exclusive since its inception it's much easier to forget about its existence.
They are announced for Steam initially. Until they aren't anymore.
Valve doesn't know about it, and the devs/pubs don't know eiher until Timmyboy comes knocking.
The only thing that Valve could do would be adding some legalese to their TOS that forces devs/pubs to always release on Steam at the same time as some other platform if they want to put up a storepage - and that just opens a humonguous can of worms that will propbably end up making things worse for everyone involved instead of actually "helping".