Well regarding the Macbook/Laptop case vs. Desktop: With me typing this on the MacMini M2 base model (8GB/256GB) retailed at 650€ I can assure you, it is a nice gaming machine hardware-wise. Not for latest and greatest AAA games of course, but I played through all the Tomb Raider reboot games on this machine (using Rosetta2 as they are non-native on Steam) on High details with 1080p. Now the major issue is software, there is just not enough games available. I do use Heroic+Crossover Wine to run some other games, but it is just finnicky and only for the pro user - not average casual gamers.
Saying this, Apple could launch a 999€ Mac Mini with focus on gamers with a custom M4 design soon, if they
had a proper Proton-like layer. Heck, size & noise wise, the Mac Mini beats the current PS5 and Xboxes. But they only treat GPTK as a solution for developers, not gamers. And I highly suspect, this is only due to the fact that they won't get any percentage from games sales, as Steam is the dominant player here.
I would absolutely LOVE this! I also know a lot of people who would be a lot more interested in buying a Macbook if this were a thing.