The GPUs aren't really a problem; the M2 Pro/Max/Ultra chips are much more powerful than Intel's integrated GPUs, are very competitive with other mobile GPUs, and are competitive with all but the high end of desktop GPUs. The main thing holding them back is they consume less electricity, which is important in a laptop, but is not necessarily important in a desktop PC.

The problem is, game developers tend to pick the platforms that will make them the most money, and Microsoft has held an uncontested monopoly on the PC OS market for more than thirty years now. They have held onto their monopoly for so long because they have the high ground on GPUs (Apple has a grudge against Nvidia that probably won't go away until Tim Cook retires), and they also hold a number of popular games that are exclusive to Windows (Call of Duty, FIFA, Madden, Final Fantasy, Counter-Strike, Fortnite, Diablo, Far Cry) whereas Apple's highest profile exclusive macOS game at the moment is Hello Kitty.

It seems like each time Apple makes gains in the PC market (iPod/iPhone halo effect, keeping controversial UI changes to a minimum), Microsoft gains one and a half times that.