...well, there are a great many reasons why someone don't drive...not just physical inability...and because we don't "see" it, that does not mean that it's not true ( I think I heard a "yes Jesus" from the religious )...
...what surprises me in Canada, is that most drivers do not obey the driving laws...or at least in Toronto...and don't even think about New York City...I was there recently, and was shocked to see people standing off the curb, in the street waiting to cross the road...and the taxis were driving like they were in the "wild west"...but here's the thing, even the cops were breaking the law...there seems to be a general feeling of "do whatever you want, and don't care about anyone else"...
or would they be better off in the back seat.