MM, fortunately instead of buying a new Oldsmobile diesel in 1978 I bought a used MB diesel. I stayed with MB until ten years ago when their quality went down too far. UNFORTUNATELY I did buy four Chevy diesel PUs at the same time with extended warranties. Most expensive mistake I've ever made as GM would not warranty head gaskets. Like you I have not bought another GM product since so it was a two person crusade and I will not buy an extended warranty either.:(
From my reading the newer XRV tires are OK but people on this forum reported their XRV did blow out while in storage and Michelin did NOTHING. Unlike 40+ years ago, there are other choices for good radial tires. I agree that Michelin makes great truck tires, but I vote with my wallet when someone gives poor service.
PS: My 03 Lexus LS430 has been the best car I've ever own with zero problems in 10 years and it's never been to a dealer since the day I drove it off the lot. I hope to enjoy it for another 10 years.:B