Everyone makes mistakes ... even genius tech billionaires.

During a recent interview with Village Global, Bill Gates spoke candidly about the biggest misstep of his career. And, no, it was the wildly disappointing Windows Vista.

The 63-year-old revealed his greatest mistake was failing to position Microsoft as a smartphone heavy-hitter. Gates insisted his company should've had the most popular non-Apple phone operating system, but dropped the ball and gave that title to Google's Android

"In the software world, particularly for platforms, these are winner-take-all markets. So the greatest mistake ever is whatever mismanagement I engaged in that caused Microsoft not to be what Android is," he said. "That is, Android is the standard non-Apple phone platform. That was a natural thing for Microsoft to win.

Gates continued: "It really is winner take all. If you're there with half as many apps or 90 percent as many apps, you're on your way to complete doom. There's room for exactly one non-Apple operating system and what's that worth? $400 billion that would be transferred from company G to company M."

Microsoft launched its own operating system, Windows Mobile, in 2000—seven years before Apple released the first iPhone model, and eight years before the original Android arrived. At the time of the former release, Microsoft's then-CEO Steve Ballmer, dismissed the $500 device as the "most expensive phone in the world."

"There's no chance that the iPhone is going to get any significant market share," Ballmer told USA Today in 2007. "No chance."

Though Microsoft had a clear headstart on its mobile phone competitors, Gates suggested the company failed to maintain that momentum because it was too distracted by the 2001 antitrust case.

"We knew the mobile phone would be very popular so we were doing what was called Windows Mobile. We missed being the dominant mobile operating system by a very tiny amount," he said. "We were distracted during our antitrust trial. We didn't assign the best people to do the work. So it's the biggest mistake I made in terms of something that was clearly within our skillset. We were clearly the company that should have achieved that—and we didn't."

You can watch Gates' full interview with Global Village above.