I would look at it like this: iPhones are a 'luxury' good, aswell as a trend/pop culture item.
The thing about luxury goods, they are build to be luxurious! iPhones aren't built to last more than 2-3 years.. Apple literally build their products so after their warranty they're to be thrown away/recycled, they want you to spend more of your money on more of their goods rather than having a good phone that lasts you a while. Asides the excessive prices even for their most basic products; their products are very premium (Even the box that your apple product comes in is carefully designed to be premium)! Just the apple logo alone lets everybody around you know that what you're using a top quality product, it feels good in the hand as well as functions extremely well!
As it stands apple was one of the first phone manufacturers to properly bring together a lot of currently known user interface design heuristics, which are little tips and tricks which greatly make a device's interface easy to use and learn. In my opinion, being the first phone manufacturer to have a simple yet effective user interface, on a phone which worked well, meant they could grab a lot of today's customers.
Some of today's apps furthermore work better on apple, examples ranging from Tinder all the way to even snapchat (snapchat on android a few years ago was such a joke, buggy beyond belief unlike its apple counterpart). This makes sense, seeing that the idea of a 'app store' was first made popular under apple's domain.
Android on the other hand can be understood by remembering that unlike apple, android phone manufacturers simply get the operating system from google and try their best to implement it onto their hardware. This is unlike Apple, who spend long periods of time creating their own operating system, and getting it to work on their specific hardware, rigorously testing it to ensure that it not only works, but works well! One could invest in a Samsung if they wanted a top tier android product to last ages (And can be fixed with relative ease outside warranty), or even invest in a one plus if they wanted a cheaper but good phone! These products like you mentioned are also easily customisable and even if broken outside of its warranty, there are many shops which can independently/refurbish repair your phone for cheap..
But yeah as you said, apple is not only 'easy to use' compared to android, but its also become a luxury good/pop culture item. Ive never owned a iPhone in my life and have been using android phones since 2010, but I've got to give props where it's due.