Have you serviced the transmission and at what intervals?
I have had the same good life from multiple GM pickups. I ran a fleet of 2500 and 3500HD pickups and we changed all the diffs, transfer case and transmission fluids at 30K, we changed belts and tension pulleys at 110K usually with the brakes at the 110K service. Can't remember being let down in the boonies in an expected life of 200k. Wasn't the cost of repairs that we feared, it was the lost opportunity of charging for our time.
But, if you take care of any brand, it will usually take care of you. Also we drove 1/3 of our miles on gravel roads.