Part of the problem, IMHO, is that the standards between vehicles are inconsistent. Just renewed my CBT for the bike this morning, with a view to taking a full licence course in a few months (I had October pencilled in for that, but even if I took to a geared bike very quickly, the wait for the local test centre is now up to December...!!). Consider what a newly qualified young learner can drive and ride..
At 17, on an automatic-only licence, you can drive a Bugatti Chiron if you can pay the bills. 1479 hp......not recommended unless you're Max Verstappen.
What can you ride at 17? Max 125cc, 14.75 bhp (A1 category, same as you can ride with a CBT certificate).
For A2 (47 bhp): 19 years old
A (unrestricted licence)- anything road-legal, even Honda's RC213VS (MotoGP for the road) bike or 200+ bhp screamers...24, or 21 if you've held A2 for two years.
To me, that's nuts...