Why don't they sue!?

Isn't Bill Gates creator of Windows therefore creator of computers so can't he sue Macintosh because I really think there's a better reason than he's just a nice guy, and if The Simpsons always claims Family Guy is a copy of them and copies their jokes (and please don't get angry FG lovers I don't agree even though I hate that show compared to The Simpsons) can't they sue as well for them copying or are they just nice I don't get