P.S. Outside of IBM-PC DOS, Microsoft already was a multi-million dollar company. In fact, they were a Unix shop and a language shop. Again, I think there might have been a far more innovative market had IBM went closed design on their PC. We already had an amazing amount of tinkerers and innovators trying to make their mark.
Microsoft was damned lucky that Gary Kildall was too nice of a guy and not savvy enough to fight the whole DOS issue.