You can see that the iPhone is still has the largest smartphone market share in the US.
Also, bear in mind that Android phones thrive in less rich countries like Mexico [2] or the Philippines [3]. The price of the iPhone is perhaps the largest burden for these people, but I'm willing to speculate that if given the choice, most would favor iOS over Android.
[1]: https://www.counterpointresearch.com/us-market-smartphone-sh...
[2]: https://www.statista.com/statistics/867948/market-share-smar...
[3]: https://gs.statcounter.com/vendor-market-share/mobile/philip...
There we go :)
Between me and Apple I'm reasonably clear about the business transaction. I pay to buy a high margin device. In turn Apple assures me that they have a vested interest to do what's best for me (i.e., my privacy, no trackers allowed etc.,).
With Android we have bewildering choice of hardware/forked-Android and what not which come with pre-burned apps and app stores that one can't get rid of.
Google Pixel comes closest to iPhone but at that price point I might as well buy iPhone as Apple has better track record of respecting user's privacy.
If Apple made it easy to put custom apps on the device it would mean you could more easily be tricked into installing malware and so reduce the trust in the security.
The iPhone is as popular as it is today due in no small part to how they have policed the App Store.