Here is a theory (I have no evidence to back it up).
Saudi is boring - I've worked there.
Entertainment of any sort is non-existent.
It's usually too hot to indulge in any sport. TV is awful.
There are very few sights or sites to see (I'm told that Makkah and Medina are beautiful, but as a non-Muslim I was never allowed right into the places.
So, if you are wealthy, and the roads are good, and your vehicle has A/C why not indulge yourself in the only pastime that is vaguely rewarding in such a miserable place.
Get a car and drive it for fun.....
