Games on PC always crash

I wouldn't say that's totally true :)

Games on the PC crash more than games on consoles though - but that's because consoles are a fixed platform - there may be one or two itterations, but the developers can be pretty sure what the hardware will be. On the PC they have to contend with different OS-es, different service packs, different drivers - different graphics cards, sound cards, amounts of memory, etc. Even stuff running in the background (Ventrillo, WinAmp, etc) could cause problems.

They have to worry about so many different possibilities, so there's more chance of something going wrong.