So far it seems like a bunch of secondary, niche, trendy auto companies have adopted HD. But Chevrolet, Ford, Chrysler - the brands most people buy - no HD. At least not as standard equipment. They aren't stupid. They aren't going to put something in that costs money for no reason. So - yes if you want to pay a lot of extra money for a German / French / Italian / English / Japanese high end import that - by the way, breaks down as much as less expensive cars - then you can get HD standard. Maybe all that stuff accounts for the 2%.
I got out of the radio business because I found myself moving and moving and moving to improve my job... or to just stay employed. I wanted my children to be able to stay in one school for an entire school year!!!
For over five years I owned an automobile repair business. I took a 10 year detour but was responsible during that time for a fleet of 150 vehicles. (Just a sideline to my primary duties.) Then I worked for six years in the auto dealership business.
Your analysis of the sales volume and the quality of automobiles is about as valid and some of the political views that sometimes break out like food-fights in these radio forums.
From about the mid 80s to about 2000, Japan ate America's lunch when it came to the automobile business. (I don't know if you heard about it, but GM went bankrupt just a few years ago.
In the last 10 years it seems like the European auto companies got their act together and they have been doing some lunch-nibbling themselves.
And now it appears that what we refer to as "Detroit" finally has their act together.
I have fun when I go car shopping. I bought one three years ago. I tell the salesperson: I buy one of these things once every 10 years, whether I need to or not! (Same story with desktop computers.) When I went in to look at cars, NOBODY even mention that they had a radio. No body was talking about engine size. EVERYBODY wanted me to get in the car and let them demonstrate the electronic dash, the GPS system, the rear-view camera and video screen, the i-pad like panel where street locations and information were available at the tap of a screen. And jacks to plug in your mp3 player or your i-phone. And a cd-player under the seat.
"Does this thing have a radio?" I'll have to go ask my manager sir. I don't know. By the way, what is a radio, sir?