Because when you are giant studio using Unreal Engine there really is no excuse for poor performance or porting. But when you are a (relatively to Epic or Sony/Microsoft etc) a tiny team building a game using the engine you came up with yourself with its roots somewhere around 2010-ish , back when 6 cores was a brand new thing and have been tweaking it ever since, you do get some slack if it doesn't multithread perfectly.

The fact that you like the game/studio doesn’t change the fact that they’ve shipped an engine that treats modern CPUs like Core 2 Quads.

Still playable on most systems. It's not like cyberpunk level of gank

edit: Cyberpunk xbox/ps I guess. It was fine for me on pc.

Because a lot of people aren't experiencing much in the way of performance issues yet? I've not yet reached Act 3 where I hear it has the most impact so performance has been fine for me, like the vast majority of the userbase at this stage, I imagine. I'll see how I feel once I hit Act 3.