Fruity tax is applicable if the game is sold through the Apple store. It is not a must for MacOS.
MacOS in my opinion is not popular for game developers because the market share is very low, relative to Windows. And gamers will not flock to Mac due to prohibitive cost, again compared to Windows system. You can't upgrade as you like as most components are soldered on. I don't think i would like to buy a brand new Mac each time I want to upgrade SSD, RAM or even GPU. Even the so called "upgradeable" SSD is proprietary. So overall, MacOS based systems won't be seeing much growth for serious gaming.
Agreed with your with apple tax but people that play consoles also can't upgrade RAM, GPU. Storage just started to be upgradable with current gen consoles.
The real problem with mac as gaming is High End AAA games, cyberpunk and crysis are out of the equation because a hardcore gamer won't buy a $7000 mac pro with about 4070 performance just to play cyberpunk.