https://worldpopulationreview.com/country-rankings/iphone-ma...
40% in some places, not even that high globally (android wins by a large margin). But android isn't "one company".
In the states, AT&T was a monopoly. They owned phones, the cables, the service, the device in your house... All of it. The rise and fall of ATT is a fascinating story, unix is free today because ATT was a monopoly (it's an interesting side effect not an argument for them).
If you dont like apple, you have the choice of android. If you dont like nividia, you can pick AMD, if you dont like AMD, pick intel. Dont want to get on that Boeing flight, take Airbus...
https://en.wikipedia.org/wiki/Duopoly they exist all over and sometimes behave like monopoly's! Vendor lock in is real... I dont want to give up my iMessage bubbles is not that much different than not wanting to re-train pilots for something other than a 737 (and we get the max).
Apple is much easier to pick on in this space because they have always aspired to be a vertically integrated company. YKK is a great example of one of these. They (ykk) make the zippers that DONT suck, they are just expensive vs everything else (sound like apple vs android).
SO while the situation with apple might be lamentable, it isnt illegal or uncommon...