right to repair

I saw the signs years ago..... of the independent, non-authorized servicers being shunned from repairing products.
I was one of them, and fought against the BS they were trying to sell.
My shop was dedicated to being versitle, diversified, and we did our best to make the customer happy.
I'm glad to be retired now, and running my small home shop the way I want to.
Car OEMs stopped supplying all but two service centers with head unit parts (n the late '90's?) which killed that part of the business.

For some car amplifiers, the manufacturers are defacing parts. For linear type amps, it wouldn't be a problem but for class D amps, they can be very finicky about the parts used and it's generally not worth the effort to test extensively (in virtually all possible conditions/loads... bench testing for hours into a couple of different loads isn't enough) unless you are going to see a lot of the same make/model amp.
When I started my auto-tech career long ago, (84) concurrent with getting my two-year EE,...I noticed two factory mis-wire jobs, one, an out of phase rear speakers on all the brand-new Honda 1986 Prelude SI cars...I demoed the fault to the main factory rep.
Another was a phasing mistake on the radiator electric cooling fans...the car would overheat at only about 30-35 MPH, the exact speed where the backwards fan velocity would match the over-the-road speed the airflow trying to pass thru the radiator.
Mind you, all the connectors were keyed, so the errors were factory.
Right in the middle of Desert Storm, myself & a handful of techs attended on of those big Factory tech-centers...in between classes I wandered outside the building...I found a large dumpster, it was nearly filled with Honda-factory stereos, all of them damaged with big holes punched thru them...a clean colorfully painted pick-axe with a retaining rope tied to the dumpster...the tool used to render all the radios obviously unrepairable. Perusing thru all the stuff, I actually found one stereo I had written up as faulty...and had done all the warranty write ups on it...it was a stripped out volume knob or some such stupid thing...but now had a golf-ball size hole punched clean thru...

In the early 1980's, for a few years, I worked for a small outfit near my old High School.
Whalen Radio, which did speedometer calibrating on GM vehicles, and had a rear shop of 5 of us doing GM Delco, Delco-Bose, and Chrysler car radio repairs.
I was one of those techs.