This situation is both good and bad. Stolen parts are good, in the sense that this grey market at least allows consumers to repair devices cost-effectively. It's also bad, because besides it essentially being theft, the grey market opens the door to bad actors who pass off used/defective/rejected/counterfeit parts as the real thing.
Repairability laws would actually help here. You would get the same repair shops in the US if Apple was forced to provide schematics & parts at a reasonable cost, with no risk of counterfeits or bad parts.
This is a big deal, and the reason there's so much opposition to right to repair, even beyond Apple. If R2R was a stupid, niche, geeky idea that doesn't bother anyone it would quietly get passed and that would be it, but the reason people are bothered by it and oppose it is because device manufacturers (whether computers or cars or farm equipment) actually make a lot of money off the status-quo.