Roger McNamee founded Elevation Partners, a tech private-equity firm with $1.9 billion in assets. He can claim Steve Jobs, Bill Gates, Larry Ellison, Mark Zuckerberg as friends. Bono is his coworker. He earned a 700 percent return saving Seagate Technology in the 1990s. But according to Portfolio, McNamee can't succeed in the one thing he really loves: rock and roll.