I'm Italian and it's mandatory to learn how to drive stick in order to get a license. This could explain why we think driving at 16 is absurd: it would probably be difficult for a 16 years old to learn stick.
Am British, and feel the same, although here kids can drive on private land at a younger age (usually farm workers), so sometimes you see kids immediately take their tests (theory and practical) at 17 and pass.
Why would it be difficult? Children can play complex video games and handle the controllers perfectly - why should a manual stick be too complex for teenagers?
I learnt stick at around 14. 37 now and still drive and prefer stick. Also just did 3 laps around the nurburgring with a stick for the 1st time a few weeks ago. A life changing experience