If I want, for any reason, to not use Amazon, I can do that easily (even if I will have to pay more, it is my choice) by typing any other online store or seller into my browser, or going to a local store.
For the typical person, they cannot use anything other than Microsoft if they want to use a computer, period. Except Mac, which many can't afford and which is limiting in what programs it can run.
Currently Microsoft does not have a monopoly on computer OS. They have practically no stake in mobile computers (smart phones). Mac has a decent share of desktop/laptop usage. Any claim that MacOS is "limiting in what programs it can run" is a 10 year old argument or so one sided (Windows is also limiting in what programs it can run....). The Microsoft of 20 years ago _did_ have a monopoly on computer OS.
You may be speaking as someone techy. For most people, what I said still holds true.
[0] http://gs.statcounter.com/press/android-overtakes-windows-fo...
[1] https://en.wikipedia.org/wiki/Usage_share_of_web_browsers#/m...