I've rebought games on Steam I had on Epic for free, just because the platform is so terrible. As far as a metric goes, that's pretty clear.

It's definitely not about lock-in for me. It's everything from local streaming, to linux support, to cloud saving working properly, to 100s of other things that become apparent if you try to do anything other than launch a game in a bog standard way on a windows machine.

Same. Sometimes I will play a givewayway game on EGS and like it enough to e.g. buy the DLC. In that case I'll buy the game on Steam, just to buy the DLC there too.

Doing Big Picture Mode well is another.

Epic have had decades to get any one of these right, and yet they refuse to meet us even half way on a single point.