I was taught to drive by my father, who was a racing driver. Drove go karts first, then scramble bikes, stock cars and midgets. Only ever had one crash and that was just after getting my first car, when a fool in front decided to stop in the middle of the road and I hit them. Learnt very quickly there is massive difference between how a normal road driver reacts and how a trained racing driver reacts. Never had a crash since luckily.
Was a quartermaster in the navy and because of my cams licence, was given a defensive driving course in Singapore. Part of our job, was ships police and we had to go collect the drunks, at the time there was a lot of trouble in sth east Asia. So we were armed and loaded, had some interesting hairy times during the riots in Hong Kong and the new territories.
When it came articulated licence, spent about a month moving trucks round the yard and then doing jobs with an experienced driver, before being let out on my own.
With road trains, almost the same, spent weeks moving trucks, trailers round the yard, hitching up and collecting freight in a semi. Then collecting empty longer and longer rigs from the stock and rail yards, finally took a few short runs in bigger and bigger rigs with the boss. One day he called me in, told me to pack a kit, gave me the inventory, said see you at the end of the week and off I went for a 5 day jaunt, which turned into 8 days.
In my experience, no matter what age, properly trained drivers rarely have a crash, especially if you've been trained on a race track or under different road conditions with someone who knows what they are doing. When you are about 50m long and have 100+ tonnes trailing behind you, if you haven't been properly trained how to handle something that big, you are 95% likely to have a problem.
Having towed caravans, to me they are more unstable on a bitumen road and less controllable than a road train on a dirt track.