I feel like there's also something of a snowball effect here because in certain genres the available set of games are good enough to rarely need to reboot into Windows. All the Paradox strategy games, X-COM, a variety of indie games built on Unity, etc. It feels like the only thing I'm ever consistently missing out on is FPS games, and even then there's been workable ports of stuff like Deus Ex.
Anything requiring more than Intel integrated graphics tends to not work well on the Mac. The vast majority of Mac models can't even take a dedicated GPU upgrade, so you're stuck with whatever Apple soldered to your motherboard and at their mercy for graphics driver upgrades.
The only time I've seen anyone try to seriously game on the Mac was a friend of mine that built a Hackintosh with a (brand new at the time) nVidia GeForce 1080ti. He couldn't even maintain 60+ FPS on Rocket League. So there's no wonder why games that require that level of GPU performance don't sell well on the Mac.
