Because Proton makes Linux versions easier to support, and the games run better through Proton than natively. That's why they cancelled further ports. Yeah people forget Linux ports were a mixed bag, versus Proton that is making games run incredible. Hogwarts Legacy runs better on Linux through Proton than it does on Windows natively.
Whatever is easiest for developers to do and runs the best, they will do, which in this case was Proton. Is that a bad thing? No. Of course not. Do Linux distro developers and Linux users care that there's no native ports anymore? Also no, as guess what: They're still getting the software they want and new users, which is all they want.
So even if we didn't get native ports of PC games on Mac and only had them through compatibility layers, who cares? The games would still be there and playable, many playing beyond expectations on an ARM SoC. Look at GTA5 and Battlefield V through CrossOver. They run fantastically even though they're not native ports. Hell God of War 2018 and Final Fantasy 7 Remake runs as good as they would on a PS4 Pro on a M1 ON A MACBOOK AIR, A COMPUTER WITHOUT ANY HEATSINK! That's incredible.
So who cares if windows games don't get ported or developed for macOS? With a compatibility layer they'd still be on macOS, and everyone will be happy. When everyone can play the same games, everyone wins.
Thanks to the compatibility layer in the Game Porting Toolkit, this comic is now officially outdated