Underrated? He is properly rated in the sense that he owns 10s of billions even though he singlehandedly killed the windows smartphone and tablet business and also killed Nokia. Granted that apple killed them but with Microsoft’s resources there was no reason to just give up like they did. Buying Nokia was a historic bad decision that screams he didn’t understand the business at all. There was a huge opportunity to just emulate apple and just suck in all of the corporate market in one swoop and add them to their recurring revenue office service but Ballmer didn’t see it. He just saw them as phones and hardware.