That's worrying.
My own thought is that this is a legacy of another new generation of parents that virtually live in their cars.
If we wanted to promote a sedentary life style you couldn't do any better than the modern pattern of 'hopping in the car' to go shopping etc.
The kids that sat in the back of their parents car in 1990 are about to be the parents of the future.
My daughter isn't driving yet but cycling around as she doesn't consider it unusual or hard work. Her friends parents don't like them cycling and will probably get them driving lessons sooner. These children though will have spent many years in the back seat watching mum and dad driving so will feel very much at home I'm sure. Human nature I'm afraid.