Never say never, and I'll knock on wood.
I'm at 317k original factory trans in my 04 Z71 Tahoe. I've towed a 21' speed boat to the river numerous times, along with a flatbed trailer with Polaris Rzr or a long travel dune buggy to the desert in the 6 years I've owned this Tahoe. I've drained the pan about 4 times since I've owned the Tahoe and top off with around 4 quarts of fresh ATF. A little maintenance and paying attn to how it's shifting has netted me way more miles out of the trans than I ever expected.
If the engine wasn't puking oil, it would be the perfect Tahoe. Instead of finding and fixing the oil leaks and past coolant loss problem on the 5.3, I decided to just build a 6.0 long block to drop in it's place. I suspect the trans will have to be attended to shortly thereafter.
YMMV....