My recollection of learning to drive many years ago was that I took driver's ed, drive my parents around a bit, but then didn't drive much/own a car until after grad school. And therefore, didn't really have much driving experience until later. (And didn't really learn to drive a stick until many years later when I bought a car with one.)

I guess I'm skeptical that having some more classroom time and a more rigorous testing improves young person driving a lot--much less makes much of any difference to how people with a few years of driving under their belt drive.

I think the tests are just the colors under which bureaucratic red tape just happens to sail. Anything that creates barriers to entry will result in people being older before they get their licenses and that is where the bulk of the benefit comes from.

Is there any evidence that young drivers are dangerous due to age rather than inexperience?

Teenagers aren't known for not putting themselves in dangerous situations.

I don't think teenagers are any less safe than an person with equivalently little experience in normal traffic situations but they are definitively more likely to be less conservative when they do decide to push the limits. There's a difference between navigating a complex intersection and knowing how fast you can/should go on an empty highway.