I think historically it was customers — it wouldn't bring new customers. It might make the existing customers happy, but I can't think of a segment of customers who are on the fence about a Mac because there aren't gaming options.

Nowadays, hardware. Apple Silicon is so far away from the existing gaming hardware (somewhat with regards to ARM, not discounting mobile devices, and the custom-built integrated GPU's with shared memory) that supporting games would add whole new complicated use-cases to their chip designs — to effectively reach no new customers.

All that said, the Game Porting Toolkit highlights that, for people to take their VR offering seriously, Apple has to take games, or at least their engines, seriously.

I'm skeptical it'll turn Apple into a gaming destination — but Apple Silicon is truly impressive and it would be a industry wide shock if they suddenly made gaming a key strategic direction.