What's a better solution? Charge more for Linux and Mac versions?
For Mac - Apple has to make gaming a bigger priority, and that's clearly not going to happen. A ~$1000 upgradable Apple machine with a powerful graphics card that can run the latest games is a pipe dream.
For Linux - It's the same problem as building any software for Linux that caters to the non-server non-developer segment. There just isn't enough of a business justification.
Most AAA games are designed with the trash hardware of consoles in mind, so laptops with more powerful GPUs handle them just fine. Apple's desktop offerings are abominable in terms of value and sticker price, but they pretty much own the non-Walmart-quality laptop market...
Once it's on there, you don't really have to worry about constant breaking changes from the operating system changing its audio subsystem or weird graphics drivers.