Apple doesn't get a cut of software that's sold outside the App Store on MacOS.
And the most performant MacOS APIs for graphics rendering aren't on Linux AFAIK. Besides, game developers generally eschew compatibility layers because they harm performance.
Maybe short term. Helping a company grow that is know to lock down their products and force developers to pay them for access might not be the best long term plan overall.
Make games for Linux, and let Apple figure out a compatability layer to make it work on their products. That's the way it should be.