Imagine being the one of the richest people in the world, and still have something that keeps you up at night. In an event hosted by the founders of venture firm of Village Global, one of their prominent investors is Bill Gates. He needs no introduction as the founder of Microsoft and Windows, but even he has his regrets. He says that Android has become the standard “Non-Apple phone form platform” and that was something Microsoft should have won against Apple.

“You know, in the software world, in particular for platforms, these are winner-take-all markets. So, you know, the greatest mistake ever is the whatever mismanagement I engaged in that caused Microsoft not to be what Android is, [meaning] Android is the standard non-Apple phone form platform. That was a natural thing for Microsoft to win.

It really is winner take all. If you’re there with half as many apps or 90% 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 [Google] to company M [Microsoft].” Said Bill Gates, Founder of Microsoft Corporation.

To be fair, Windows did try in the smartphone market, but it just failed. The app store wasn’t great, the UI confusing, and the specs on their devices weren’t the best. Naturally, Windows is the rival to Apple. But in the smartphone market, Google has conquered, and I don’t blame Bill to still regret it.

I mean, $400 billion is a lot to lose.