No, I'm not an Engineer, but I did spend 30+ years on the "other side";
On-Air, and Programming. Clearly to me, AM Radio hit the hard slide due to not what was done, but what was simply not done. We still sell the camera, but not the film. Both Detroit, and the FCC did not do what would have built, and susstained backbone. What the factory car units could be, as opposed to what they are. AM Stereo should have had a chance to compete. I often wonder why the MD Mini-Disc recording format didn't last. It was featured well, and you couldn't touch or damage the playing surface, yet no longer.
To me, the Auto side will always follow what the FCC does, so here again, it's the Government's falt!