Their worst failure is allowing games with Denuvo on their store.
Basically, it creates a failure point for setups that should otherwise last and be stable several more decades.
Look me in the eyes and read this quote to me again. Then think about how yourself from 20 years ago would feel about reading this quote from someone else. You've gone so far down the rabbit hole but you don't realize you're in one.
My biggest gripe with Valve right now is that I bought a copy of No Man's Sky on GOG, and then I also had a copy on Steam. And so I let my son play my Steam copy through Steam Library sharing so we can play co-op while I play my GOG copy. Unfortunately, because I launched my GOG game through Steam, Steam's DRM won't let him play at the same time as me because they think we're playing the same copy.
It seems to be that they simply look at the title of the game and or the executable name to figure out what game it is, but they don't check to see what storefront it was bought from. I'm not sure about this though, I have to do more investigation.
I'm no fan or DRM, but the current implementation is far from "always-on".