I'm not arguing with you about the rims and what kind of tires they can use.
The real question is, "Why don't motorcycle dealers want to put car tires on motorcycles?" WE can debate that all day long. But the only person who knows the real answer is the dealers. And THEIR LAWYERS.
I would love to see a motorcycle manufacturer's or dealer's lawyers reply to this thread about it. The LAST thing they are gonna say is because it isn't "profitable". They would all say (if you could get them to even say it), "From a litigation perspective, it's scary as h*ll".
The only people a lawyer has to convince is a JURY in most litigation lawsuits. And juries are notorious for ruling, "Let's screw the companies!!! They can afford it!!!!"
And I'm already familiar with "Moss-Magnusson" and what goes on in courts with attorneys. I was a First Sergeant in the Air Force for 6 of my years in the military. In that capacity, I dealt with both the Staff Judge Advocate's office (the plaintiff attorneys), and the Area Defense Council (the defense attorneys). It was a fascinating education. If you ever want to know how to NOT get selected for jury duty without facing a contempt of court charge, just ask.

opcorn:
PS - I'm not arguing with you. Heck, I respect what you did as a law enforcement officer. Thank you for your service too.