Well, I'm more or less "expanding" rather than moving.
GamePass sounds like a great deal for the gamers who didn't have Xbox library from previous generation(s) with very little cost to boot.
Most games that I like - such as Falcom and Atlus games or similar often don't find its way to Xbox side - and limited or very delayed released on PC side, so I am pretty much stuck in Sony and Nintendo side. Not particularly because I'm attached to Sony or Nintendo - but to the games on them.
I understand people going PS/PC route though - but I also like playing games on console. Of course you can get better performance out of PC, but I like simplicity of console gaming experience, even on Xbox.