Cats, like humans, are individuals. I've heard tales of cats who hate to be indoors all the time, make very clear they want to go out, etc. There's one in my neighbourhood who goes for walks on a leash. I've spoken to the person with him, who has two cats - the other doesn't want to go out, the leashed one loves to go for walks. He doesn't try to run around, btw, he walks along placidly, with slack in the leash, like a bored dog, until he's had his fill, then they go home.
The poster above's grandmother spends half the year in an RV. That sounds horrid to me, but plenty of people love it. There are cats who wouldn't like to be indoor-only, but plenty are perfectly content.
The thing about cats is that they don't give a damn. If they're peeved, it's fairly obvious. If they want something you can attain with the use of the magical opposable thumbs, they make that fairly obvious. If they're happy cats, it's pretty obvious. There are nomadic humans, and there are ones who like to come home and lay on the couch. There's something to be said for warmth, shelter, reliable, good food, entertainment and love.