Edit: I'm not saying that he WANTS to be a multi billionaire, but the fact is that he has attained disproportionately less value than he's created. By rights he should be one of the wealthiest people in tech. He might have 150m but that's peanuts given what he's done. The wealth of the guy who made Instagram dwarfs that. The guy who made Whatsapp has a net worth of 8b.
Creation might be 90% perspiration as he says, but perspiration doesn't equal success, and success doesn't equal a career. Obviously everything isn't about money, and Torvald's legacy will be timeless. But if you want to ensure earnings, at some point it's a good idea to sell.