That was the situation when I was 16-17. Want transport? Get 2 wheels. It wasn't just the purchase price - maintenance, running costs and insurance were all factors*. If they had a bit of cash and could afford lessons or someone was willing to teach them most went for a car asap. I imagine lots never had another bike/scooter after the first one. Some got the bug though. (I imagine a few bought them in later years in a fit of nostalgia for their lost youth too ).
Wonder what the difference in insurance costs for youngsters in the UK and France is??
*My first cost me £35 - from a dealer! + iirc £7 pa insurance. Happy days!