I'm seeing deja vu here in some ways....though the fact that huge expenses come into the mix is different.
When I started riding, at sixteen as a learner you could ride up to a 250cc bike solo, or any size if it had a sidecar.
The 'cool' kids - the Mods - rode scooters, the largest of which (excepting a few German makes, which weren't cool anyway) could be ridden on L plates - Many of them didn't bother to take a test (they just took off the L plates when they carried their girlfriend on the back) then once old enough, at 17, they'd buy a car. There was no obvious difference between a learner bike and a 'proper' bike so they could all look 'cool'.
Those that rode bikes would try to get their test passed as quickly as possible, because they wanted a bike that would keep up with their mates....and not be marked out as lesser mortals by only riding little bikes.
The sidecar option for learners was also pretty popular as you could carry passengers in the chair while on L plates . (Solo learners could only carry a passenger who had a full bike licence - and the pillion seat of an outfit with L plates was also only available to full licence holding passengers.....Don't ask me why!)
Whichever kind of two wheeler you rode, you wouldn't be likely to be riding for more than a year on L plates.
The other option, a three wheeled car like a Reliant or a bubble car could be driven at sixteen, but a full licence holder (either car or motorcycle) had to sit alongside you unless the car had only a driver's seat. A few bikers owned three wheelers as well as bikes to keep girlfriends happy in the wet and cold, as they could be driven on a full bike licence back then.....I had an Isetta bubblecar, along with my 650 BSA café racer. I didn't bother with a car licence till I was 30.
I really despair for the young bikers of today....it really is too bloody difficult and expensive for them to get onto two wheels.