you forgot to take into account that most phones are replaced because they break - usually their display gets smashed. In this case budget phones come ahead too:

Let's say you drop your phone after 2 years of use.

If you got an iPhone X you need to spend around $300 on a screen replacement or sell if for $200.

If you got a 2 year old $300 phone you just buy a new for $300 (or do the replacement for $150.)

But anyway I really dont see a reason why someone would get a $500+ phone. I has better hardware (which most people wont make use of) and better design/bragging rights. What can do a $1000 phone better? A better camera (for most should not matter, instagram/facebook compresses your fancy images to shitty JPGs), a faster CPU/RAM (nowadays its barely noticeable unless you play stuff like Fortnite on your phone)