Gary,
I'm sure #1 is not literally true - cabs were no doubt available for some models when most local tractors were purchased, but I think not common. I don't know the ages of most of those around here, but my 17-year-old JD is clearly substantially newer than most of them. And I have actually seen a couple in use with cabs, but they aren't common. When I bought mine new I was never offered the option to get a cab, and thus never even considered it.
Terry
The next time you are traveling S. on US 421, stop at the Kubota Dealership on the right just before you reach the Parkway. The last time I was in there he had a couple of cabbed units. Also the New Holland Dealer in N. Wilkesboro had cabbed units the last time I was in there. So it would appear that cabbed tractors are slowly working their way up the mountain.