I really wish Apple would pay half the attention they pay to ATV+ to gaming, now that iOS and Macs will share a common platform, they could build/brought in house an umbrella of studios just like Microsoft Xbox Studios and PlayStation Studios to develop triple A platform exclusives that make Apple TV, iOS and Macs a first class ecosystem for gaming. They could also have a fund to lure third party players to publish their titles on the common platform.
I agree that luring in third-parties could be a good idea: now that iOS has mouse support + better controller support, and now we know without a doubt the hardware is more than capable enough of running things like Tomb Raider, bringing in a big name developer could get things rolling and show that it's possible to reach the millions of people who own iPads/iPhones/Macs/Apple TV with quality games. I can't think of anything (that isn't a port of a decades old game) that's been done besides Monster Hunter Stories, and not really sure how successful that was, but something backed by Apple marketing and funds could do better.
That said, Apple just doesn't care about gaming lol