MS already doesn't have a monopoly in any meaningful sense anymore.
- https://gs.statcounter.com/os-market-share#monthly-200901-202507 - in early 2009, almost 95% of web usage was from Windows, by now it is at around 28%, no longer even the most popular OS, which is now Android around 42%
- https://gs.statcounter.com/os-market-share/desktop/worldwide/#monthly-200901-202507 - even looking only at the desktop and ignoring the shift to mobile devices, Windows fell from ~95% to ~72% during the same time period, mostly losing to macOS but more recently also Linux
Windows isn't the main way Microsoft makes money anymore anyway...