He is not my hero, but:
Bill gates did a number of decisions against the mindset of the time, and made computing available to the masses. While other companies required you be in some kind of exclusive club to interoperate, MS allowed to run basic on pretty much everything, even low priced systems (C64), and do everything with it and never demanded that anybody writing programs for their OSes paid them a fee or asked them for permission. The path to put computing to the masses (and go outside the idea of exclusive deals) was probably seen risky, and could have gone wrong.
And while i personaaly mounr over the suffering of OS/2 from a technical viewpoint, i am not sure that staying together in bed with IBM would have done the world much good (although i am sure the short-term revenue could have been higher for MS).