At the risk of seeming like a grammar Nazi, Bill Gates did not, in fact, invent DOS. He bought it from another guy and then marketed the shit out of it, so that every IBM compatible machine (what we now call a PC) ran on his DOS operating system.

He practically gave it away so that the machines would run an operating system on which he owned and on which he could then build the most compatible and best running software to run on the operating system. He didn't make much, if anything off of DOS and windows, but has been gouging the world for decades for the software that runs on it. It was marketing genius.

I don't mention it to be a doosh or to correct your point, I only add it because it seems to reinforce your points on how to achieve success.

Anyway, cheers!