So I’ve had a 2017 Colorado that seen the shop zero times in 80k.
Dad has had two Silverado 1500s in that time, current one has 80k with the 5.3 and no issues
Buddy has a GMC Sierra 1500 with the 5.3, 90k no issues.
To muddy the water some - and to be honest and not fanboy a brand - my BIL had a Silverado 1500 that the radiator went up in at 65k. They wouldn’t warranty it. He uses his truck as a work truck and beats them pretty bad. He traded it away on a Ford with the 3.5 and has had zero issues since - this has been 3 years or so ago.
In all of the above cases(save for my BIL) the trucks weren’t heavily modified or beat on. They upgraded the tires to a good AT and that’s it. No crazy lifts, massive oversized tires, offsets, etc.
I’d be willing to bet most reliability issues stem from
1. People adding lifts/massive tires/etc onto a stock truck. Like I mentioned in a previous post, newer 1/2 ton trucks especially are engineered first and foremost for fuel economy. While it might not seem like much, adding stuff like lifts puts additional strain on the truck that it wasn’t designed for. Think about tires, a stock sized highway tire weighs like 35-40lbs each. A LT 35” tire can weigh upwards of 60-80lbs each. That’s a whole lot more weight that needs to be rolled every time it moves. The lift adds additional drag. Offsets put more stress on the drivetrain in general. Add it all on a truck that was engineered with stock height to limit drag, no offsets and highway tires that weigh 40lbs each and you can see it putting a massive amount of additional wear on the truck.
2. Beating the shit out of it. Self explanatory. Take the aforementioned truck with all those add ons(or even a totally stock truck) and run it down some logging roads or dirt roads not worried about the ruts, holes, rocks, etc at higher speeds and tell me how long your stuff lasts. Even the 2500/3500 trucks won’t stand up to this although they’ll hang on longer.
3. Just downright neglecting maintenance. “Oh my transmission is due for service, stupid stealership it’s working fine”. Neglecting oil changes. Neglecting drivetrain services. Neglecting intervals like spark plug replacement or otherwise. All detrimental.