The real problem is that phones depreciate so quickly that replacement parts (especially displays - Samsung LED screens etc are notoriously expensive) are often more expensive than buying a new second-hand phone on eBay unless you're willing to go down the route of separating bonded LCDs from glass/touch sensors is economically viable but that is much more difficult to do right, even with the right equipment (temperature-controlled hotplate).
Just replaced the screen on my Mi Mix for about $100 plus an hour or so of my personal time.
I'm projecting from impressions I'd made since the Mac book pro became harder and harder to modify and upgrade. I'd constructed a faulty assumption about the repairability of iPhones.
It's never been difficult for me to find someone to repair one of my old iPhones in the past, I just quit on iPhones last year and feel somewhat disappointed with them since the v7s. (I am a fairly recent switcher to Android.)
My phones and laptops are small enough and lightweight enough.
Making them bulletproof is too expensive. But making them easier to fix, documenting the process and authorizing repair shops would do be great.
PS: I don't need to be able to hot-swap parts.
PPS: pro models from Dell and HP at least are often quite easy to disassemble and fix and I think you can often source parts from eBay for years after you buy them.