Surely my damaged 4 year old car will be easily repaired at a reasonable price by a skilled mechanic at the car dealership who have parts in stock and tools ready to go. It would be absolutely wild if their price for that service was based on the price of the latest model year car. But certainly they wouldn’t be able to get away with that, thanks to the thriving third party mechanics.
Oh, except… yeah, these are the exact same thing pretty much. The only difference is cars have many more components and individually they cost less, whereas phones only have a handful of components and each cost a considerable portion of the phone cost.
Your specific complaint about the iPhone 12 mini seems extremely unfounded, as well. Their repair cost (which is totally turnkey) is $89. Seems extremely reasonable for a turnkey repair from a first party vendor. Surely, maybe you can buy a “new” 12 mini for $200… but this is just like cars. At some point it’s “mechanically totaled” and the repair cost doesn’t make sense. And that point changes for a car too, depending on if you use a dealership service department or a third party mechanic.