Last year, I pointed out how many big publishers came crawlin' back to Steam after trying their own things: EA, Activision, Microsoft. This year, for the first time ever, two Blizzard games released on Steam: Overwatch and Diablo 4.
Epic is worth 5 times as much as Valve and EGS is still fucking garbage years after it launched. If anything, Valve is the underdog here, yet Steam is objectively better than every other store. It's not their fault if competing products are trash. Valve is not responsible for UbiSoft being incapable of making software that works as advertised, of for Epic refusing to support Linux.