Apple has had its up the rear end regarding games on laptops and desktops for ages now, and they seem to have been blind the whole time.
Being unable to upgrade components while also pricing upgrades to outrageous levels is one hurdle. Software wise it's a PITA due to the toolchain needed if Xcode is being utilized in any way. Then you have upgrades and lack of backwards compatability (though should be mostly OK these days) to throw in there also.
High end gaming requires good hardware, and good hardware is quite costly on a Mac although the baseline performance is often quite good. One could also throw in the mix gaming monitors and how macOS looks terrible on non-retina displays, though not the biggest issue for gaming in that sense.
Apple have never understood this segment and rather boxed things in too much, especially after the Intel era. It annoyed me so much that they couldn't at least produce a mid-tower for power users instead of having Mac Pros, though I understand the segmentation. They had plenty of chances of being a bit more nice to users overall, making it easy and interesting for tinkerers to go over to the Mac, but they squandered it every time.
People aren't buying Macs to play games, that is just incidental, and until they really make enourmous strides with certain issues, especially cost of upgrades and even being able to upgrade yourself even, they won't make a dent at all. The "gamer" enthusiast has always wanted to change components themselves, I have been one of them for a long time, and Mac is laughable and antithetical to what end users want regarding gaming. If they don't mess around with hardware, they buy a console.