"anyone can opt to use alternative platforms"
Can I install an alternative platform on a iPhone or iPad?
And that was true for Windows as well... and there was no hardware block. I've used OS/2 3 for a while myself, until it was true nobody would develop application for such system - because of MS dominant position.
And I would like to see Microsoft kill Office applications on macOS and iThings... and tell for "security reasons" you need to use them on Windows only. Apple would lose a lot of the exec/managers market.