If the last 15 years are any indication, in less than 15 years, Microsoft will make Azure Linux their main OS and they'll skin the desktop edition to resurrect Lindows. It'll take a 2-5 years campaign to move most of the remaining Windows user base to it. Oh and also, it'll probably be free.

In 15 years, Windows will still be running hospitals and governments and Linux will have dropped back well below 5% desktop usage because using Linux on the desktop in the modern day is an ideological decision and literally never a technical one