I agree that for the sticker price of these trucks, especially a Denali ultimate, that we should expect better longevity and build quality. Trouble is that I don't see any manufacturer hitting it out of the park on this. I've driven GM trucks for over 20 years, but am willing to consider other brands. Take a look at FoMoCo boards for the F150. Again it may be internet amplification but seems if Ford has no clue on how to produce an engine that doesn't have issues, rattles, cam phaser issues, oil leaks. Again a look at FCA sites and you'll see rattles, lifter issues, electronic nightmares, etc. Not defending GM at all but don't know who else does any better. I did own a Toyota Tundra a few years back and it was NOT anything impressive in its short babied life at my house. Failed front rotors, failed radio. rust issues on the front bumper, trim that fell off, etc all in 40K of ownership. My current 17 Denali has been ok, but suffered a direct injection pump failure which resulted in fuel being dumped into the crankcase. Doesn't seem to have affected it as it was caught early, but I still wonder about long term effects. My next truck may be any brand; it really seems to be a crap shoot if you get a good one.
Best of luck and maybe GM will step up and offer some help on the failure.