People could rationally decide that prolonged relationships take up too much time and effort and that they'd much rather do other kinds of things. But most people are afraid of rejection.
For the most part, having more money and more fame make your life harder. It just does. I've seen it happen with people. You know, it's so hard to stay normal. It's so hard to stay happy. It's hard to remember why you were doing what you did in the first place.