According to Linus, his reasons for creating the kernel were, as quoted from Linus in "The Code"
I didn't want anbody else to have to go through the same thing I had. Your trying to find something like Linux, so I decided hmm, maybe some other computer science student out there needs his own operating system then he doesnt have to start from scratch. It wasn't the big fight against the windmills it was not Don Quixote against the world trying to, to make a better place.