The ONLY way the demographics of game playing on Macs is ever going to increase is if Apple constructively focus on building gaming Macs.
I don't think it's the only way or even the best way. Gaming Macs will always be more expensive and less attractive than PC counterparts, for the vast majority of users. Yes, Apple may release ultrabooks that run games better than comparable PCs, but I don't think it'll make much difference. Desktop PCs will remain much better at gaming than Mac towers (larger choice of GPUs, more games...).
What Apple could do is release a gaming-oriented AppleTV (in essence, a console) bundled with a gaming controller and sufficient storage (1TB at least). If this comes with an M1 or M1X, this would have better performance than the PS4 or PS4 pro (if it gets the M1X). Apple would tout the ability to play the same game on your Mac, Apple TV, and iDevice (if the game isn't too demanding).
It would have to be priced reasonably (< $300). Apple would have to make profits form the software, not the hardware, otherwise it would not stand a chance against competing consoles.
But Apple is late to the party. They had a chance to make the AppleTV a better game console, and they screwed up.
Also, I don't think Apple is willing to sell hardware at a loss, which is what all console makers do. The console business model is very far from Apple's business model, yet making a game console is their only way to attract AAA games, IMO.