Yes, what you're describing is exactly what I see: The kids who "remain involved" are the kids whose parents have more money and are able to provide for them. Of course, it's not a 100% true thing -- exceptions abound -- but it's a general truth.
I also know of a few kids who are driving -- with their parents' knowledge and blessing -- without a license and without insurance. I first became aware of this years ago when one of my students asked me if I'd Xerox his driver's license for him. Our county policy is that if a student is attending a dance at another high school, the student must provide a Xerox of his license so the school knows who's in their building /the student's age. I agreed to make a copy, but when he handed me his license, the face was all scratched out, and it wasn't his name. Clearly he was trying to pull a fast one, and I refused to help him. He laughed and explained that it was his cousin's old license. He said, "Everyone does it." I asked him if he is actually able to use the license with the face scratched out, and he admitted that he's never been stopped by the police. I believe that: In 30-something years of driving, I've only been stopped a handful of times. My oldest has been driving 4 years and has never been stopped. I felt awfully unaware that day, but since then I've become aware of other kids doing the same thing. Apparently their parents are able to scrape together $1000 or so for an old beat-up car, and one of the ways they afford it is to bypass what you and I consider "the necessities".
The real moral: Don't skimp on your own uninsured motorist insurance.
I know a few kids who aren't interested in driving AT ALL -- often it's fear underneath this issue. When I was a teen, I knew no one who wasn't chomping at the bit to drive. One of my dear friends didn't drive until she was 18, but that was because her parents forbid it. One of my brothers waited to drive, but that was because our parents had insisted upon some rather stringent requirements, and he had decided it was just easier NOT to drive. I agree with you, however, that you should push him to learn while he's still living in your house and you are able to provide him with plenty of supervised driving. You don't want to send him out to college without having this life skill under his belt. If he doesn't drive regularly, no problem -- but he will know how.