There's no school-based driving education in the UK either, so along with the later start date of 17 many drivers don't begin driving until they're in their mid-twenties, or even later than that. The average cost of learning to drive in the UK is £1,128 GBP/$1755 USD for lessons (
source 1,
source 2) and total cost of learning to drive is around £2,741GBP/$4264.58 (
source 1). So a lot of Brits who grow up without financially comfortable parents have to wait until they have a financially stable career themselves. A lot of people (moreso in big cities like London) don't ever learn to drive and rely on public transport instead.
I'm forever envious of American buddies who get driving lessons in school and only need an hour or two or practice before they pass. The UK process is super slow, and a lot of driving instructors milk the lessons far beyond the DSA-recommended 47 hours. The US system is SOOOOO much better. (I base this opinion not on safety, or better education, or any of that... just that I'm learning to drive right now, after a year of one-hour-a-week lessons, and any system that leaves me less broke than I currently am seems godly.)