Ah, let's not forget the army
Ah, let's not forget the army of small independents out there -- and some of the majors who won't tell you such things to your face -- who do open the backdoor when the truck pulls up with the parts no one wants them to see. To say that it doesn't happen ignores human nature. It does, indeed, happen. Of course, dealers aren;t using them and neither are major chains but how many small scrapyards are out there selling parts? How many "JC Whitney" catalog types are out there selling the parts that old document used to hawk. do you think they diappeared? No, they have just gone to Craiglist or Amazon as a vendor of eBay or onto one of the many smaller networks that need advertising support.
Yes, you do make good points. However, some years back I remember an issue with Mopar parts and others that appeared to be Mopar and some had Mopare or Nopar names. Near enough the original to make people think they might be real and just misbranded.
Add to that the underground market for cheap parts.(To say it doesn't exist ignores a large reality that it does, folks just don't talk about it in polite company.) It's an underground that has its branches in all the states.
No I am not a conspiracy freak! Far from it! I have just been around long enough to have seen enough things to know things that aren't supposed to exist really do, in one form or another. I had my first experience with an engine in 1962 when I was a kid and we tore down and did a bit of tweaking to our Dad's old Briggs and Stratton, early four-cycle, gas mower. I have been licensed for more than 50 years. And, I have been reporting on cars for 45 years. Like I said, I have seen lots of water under the bridge and I was speaking from experience.