Given they accommodate over 50% of United States residents[0], I'm not sure the band is as narrow as you say it is. Of course, for those it doesn't accommodate, there is a different product that hopefully better fits their use cases.
Market share is irrelevant if there’s a high enough barrier to entry and cost of switching for the user. For instance Comcast probably has a very good market share and competitors too on paper.
Is the cost of switching that high? People at the phone store do 'data transfers' already (seemingly just texts, pictures/videos, and contacts), and, hilariously, the transfer to Android is a lot better than the 'move to iOS' app that has terrible reviews[0]. I bet most of the time being spent on switching will be on reinstalling all your apps and logging back into them.
It is, depending on how long you've been using the platform.
For instance if you've been on iOS for a few years and bought a healthy amount of music, those are virtually gone after moving to android. You can mitigate that by either
- forever keep paying Apple through an Apple Music subscription
- somewhat extract the tracks and DRM free them (tracks were DRM free when bought from the Mac, but not when bought on iOS last time I tinkered with it). Of course Apple will make as hard as they can to block this route.
Same for movies and books, and for games/apps as well if they don't have a multi OS pricing scheme.
Switching cost is not just time spent to get used to, more often than not it"s a non significant amount of money lost in the process.
Same deal the other way round of course: Google is more diligent on exposing their content on iOS, but there will stil be paid games and apps to be lost in the process.
0: https://9to5mac.com/2022/09/02/iphone-us-market-share/