It is interesting how the US are continuing to adopt Apple/iPhone in contrast to the rest of the world. I think its one of those things where once the majority take hold it becomes set in culture which further embeds the trend.

It is a US company, that likely helps a little. They are expensive. In many countries 55% could not afford them. Easy access to Apple stores to fix issues is a massive advantage.

Anecdotally, my friends and family that have switched have done so because of malware. Apple is far from perfect, but Google has done a terrible job of keeping bad apps out of the Play store. And malicious software has other ways of getting installed. My sister was a diehard Samsung user, but reluctantly bought an iPhone when she started getting porn pop ups and her and none of her friends could figure out how to stop them.