I knew a guy who used to run one of these little repair stalls, almost all of his parts came from stripping down stolen devices he got from local scallys. These were all genuine parts, but it made stealing these phones more lucrative.
Seems like that market could also be hurt by apple just offering genuine replacement parts
I guess cost would be a factor. It seems like they could also offer some sort of service where phones can be reverified if the shop can evidence where it got parts.
or have them be one time programmable, so you can use new replacement parts from apple but can't transplant them. although in terms of e-waste that's still not ideal