"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."
That helps explain Gates talking to IBM. It doesn’t explain IBM’s taking the contract, or their massive blunder in allowing Gates’ non-exclusivity clause on the OS.
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.
"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."