Gates seemed to be the only one who understood the value of DOS initially. Not you, not I, not Gary Kildall, not IBM, not Tim Paterson.

There were thousands of other people involved in the industry at the time. Many of them understood the future value of personal computer operating systems.

Any idea how he got to that unique understanding? Is that something we can learn from?

If you read http://gunkies.org/wiki/Gordon_Letwin_OS/2_usenet_post closely you'll understand the key business insight about the value of platforms that underlay a lot of Microsoft's success. And further see how Microsoft's continued success required a series of good decisions that capitalized on the famous lucky break.

If I knew how, I'd be a billionaire myself :-)

Sure. But if he didn't have access to that money, would he still have been able to do that?

Yes. An aggressive entrepreneur like Gates would be able to rustle up a few paltry thousand in investment capital. People do it all the time.

That is a necessary but not a sufficient condition.

His personal connections and family wealth were a lot more significant than one loan.