I agree that forced exclusivity is bad. I absolutely disagree with your statement that ubisoft store was better than steam, I don’t even understand how you can say something like that. But yes, without the games any store is worthless.
You didn’t respond to my question though, so I’ll repeat it: even if someone was able to launch a product with feature parity to steam, why would anyone migrate?
Please Proton team port over this UI to drive.