Here's my .02¢
Tires ARE made of different compounds than a few years ago, that's 100% fact
New trucks are more fuel efficient, and yet can carry, and haul more than in the past
I'm not arguing the fact that there's issues, every manufacturer has issues.
GM has known about "beam shake" for a few years
My dealer stepped up, did their best which was great, Michelin tires made a huge improvement, rode perfectly for around 5,000 miles, then I think I felt the 75 mph vibration coming back. At that point I decided to make the truck look the way I wanted with aftermarket wheels, little lift, and larger tires. So far so good.