For me, the big problem with mac gaming is that my $3k+ work laptop has a fairly shitty integrated gpu and even the dedicated gpu is pretty low end compared to what you can get in a non-mac laptop.

This means that, even though 1/3rd of my steam library has mac versions, half of these games don't actually run well.

(Disclaimer: since switching to mac, I typically game only on PS4 nowadays, which I guess probably doesn't have better hardware, but at least has well optimised games and lots of awesome exclusives)