We don’t really learn the reason, we just memorise the word for the number. Kinda like you know the word “dog” means a four legged cute creature, but not why the name is “dog”. The old rules are not something we are teached, I just got curious after a confused foreigner made me think about the system for a second :p
I’m European. I’m not talking about American cars.
And it’s also a joke with a bit of truth to it. They do require much more care so they’re more often in the workshop than, say a Toyota.