That's one of the biggest business mistakes ever.So that's a huge amount of luck.
So I'm not sure Microsoft is so unique with regards to "return on luck".
"In 1980, she discussed her son's company with John Opel, a fellow committee member, and the chairman of International Business Machines Corporation (IBM). Opel, by some accounts, mentioned Mrs. Gates to other IBM executives. A few weeks later, IBM took a chance by hiring Microsoft, then a small software firm, to develop an operating system for its first personal computer."
Lots of companies contracted with IBM without IBM signing off their whole business to them.
Bill Gates clearly was very fortunate in his life, but it’s a mistake to chalk the IBM blunder up to 100% luck.