Disclosure: Most of the vendors noted are clients of the author.Windows arose after IBM behaved very unlike itself in the 1980s as it looked outside itself for technology from then-young companies Intel and Microsoft.
The move led to AMD, created an alternative to Apple & and nearly killed its own then-predominant mainframe program.
Early on, DOS was merged with Windows to compete with the macOS, but IBM and Microsoft eventually went separate ways.
The revolutionary model (where hardware and software were divorced from each other) lived on, however, until this month when Microsoft effectively killed it.The Microsoft move, while disruptive for PC OEMs, should result in a better user experience.