Not sure if licensing is the right approach.
Education at schools about traffic safety & laws should be implemented, from childhood all the way to high school.
In many countries around the world, cycling and traffic laws are part of curriculum required for their schools.
Cycling should be like a life long skill that everyone should know, like swimming.. or maybe even math.
I feel that in America, most drivers think bicycles & motorcycles don't belong on public roads, which is a mentality that's been imbedded across decades of car culture and cheap oil in America.
As a teenager (in the 80's), I pedaled across the N American Continent from Seattle, WA to Ocean City, MD, on a Huffy 10-speed packed with 35-40 lb. of camping gear. Long before the time of cell phones & GPS. The slower pace gave me the chance to see America at 15-20 mph and how Americans really lived along the way.
Nowadays, I don't think most people in America even bother to try to understand how the rest of the country live. More over when homeless people in the streets are considered to be criminals and the real criminals getting government bailouts, tax breaks & tax write-offs for private jets or yachts.
Meanwhile, I still think parents should also be held accountable when their child is caught breaking traffic laws, causing accidents on high-seed e-bikes. If they can afford high cost, high speed e-bikes to for their children, they can also afford higher (x5 or x10) auto insurance premiums.