On the subject of replacement parts cost vs total Apple 1st party repair cost, a recent video I watched by UK YouTuber "Mrwhosetheboss" did a comparison of cost, turnaround time and other aspects between three different iPhone repair options and highlighted some of the dynamics at play:
From my admittedly biased outside perspective, the repair process he experienced (and previous coverage by multiple other outlets about "DIY repair with official Apple tools") certainly strongly suggests that Apple is trying to do as little as possible in terms of pricing & availability to support 3rd party or DIY repairs to meet their legal/PR obligations.
So, if official 1st party parts pricing isn't competitive with total 1st party repair cost I'm going to assume it's intentionally obstinate behaviour and that the blame lies wholly at Apple's feet.
* "Phone repairs are getting ridiculous - Here's why.": https://www.youtube.com/watch?v=oreZytDYoEU
From my admittedly biased outside perspective, the repair process he experienced (and previous coverage by multiple other outlets about "DIY repair with official Apple tools") certainly strongly suggests that Apple is trying to do as little as possible in terms of pricing & availability to support 3rd party or DIY repairs to meet their legal/PR obligations.
So, if official 1st party parts pricing isn't competitive with total 1st party repair cost I'm going to assume it's intentionally obstinate behaviour and that the blame lies wholly at Apple's feet.