I figured out the solution to our problem. Don't switch to PC, but get a PC. Yeah I know I'm supporting PC's on a Mac forum, but honestly both of them are good in different ways. If I were you I would go ahead and build a $1000 gaming PC capable of running anything on high, and keep your Mac for things besides gaming. Best of luck!
Hah, that's a good solution.
Personally, I'm tryyyying to avoid it if I can - not because I'm anti-PC, but I've a small apartment that is already cluttered up with Macs, routers, cable boxes, consoles, power cables, extension cords... I'm almost on a "one box in, one box out" strategy. So if I bought a gaming PC, it would probably have to replace one of the consoles under the TV.
It probably is cheaper though, to get a Mac mini & a ~1,000 gaming PC, than to get a bottom-end Mac Pro. I'd still prefer to support Mac game developers/porters though.