I did a lot of enterprise risk management consulting over the years and a fair amount in the auto industry. I was also around the retail side some as a kid. Long before I came along, when my father was a young man he had a Nash and Hudson dealership and he remained loyal to the brand. I spent a lot of time on road trips as a young child in a Rambler Cross Country station wagon and took my driving test in an AMC Ambassador. While I was growing up my Uncle Clarence had a Chevrolet dealership and there was a Ford dealership in another branch of the family. No matter what make you drove to our annual family reunion, you were certain to make some people angry
At least there was only one tractor dealer in the family (Deutz Allis) so that didn't create too much controversy.
I am still pretty GM brand loyal and although I wish they would have done a better job with the 8L family, the 8L90 in my 2016 Z06 has worked perfectly except for the need to manually shift to second gear while stationary at the first start of the day to avoid an initial rough 1 to 2 up shift. I either leave it in manual mode or have a Range anti-AFM module in place to avoid the continuous converter clutch modulation in V4 mode that is likely a large contributor to the shudder issue. If the latest (version 4 if I count correctly) ATF fluid formulation revision continues to get good reports, I will have that done before it goes into hibernation for the winter.
One now humorous historical industry footnote: Before the "Japanese invasion" when the feds were concerned about anti-competitive concentration in the U.S. auto industry at one point there was a real risk that GM and Ford would be partially broken up if the industry became more concentrated. So GM, and to a lesser extent Ford. began bidding on some large government fleet contracts and then supplying AMC products in order to help AMC stay in business. They knew that was the tipping point and if AMC failed then it was highly likely the justice department would begin anti-trust proceedings against the bigger 2 of the then "Big 4". Of course by the time "Franco American" motors finally failed under Renault, the market looked a lot different and a monopoly of the remaining big 3 was no longer a major concern. When International Harvester was still making SUVs and pickups, a major strike cut into their engine production ability in the very early 1970s and they ended up using AMC produced 401 V8 engines in place of their own SV-392 in light duty vehicles. An old timer I knew said that several sources were considered but they had an existing relationship with AMC for inline 6 cylinder engines and Ford and GM both refused to deal with them because they were a competitor to their own light truck lines AND it was another way to send business to AMC and avoid their own breakup. The ghost of AMC lives on in AM General (best known for the Humvee and civilian Hummer version) because at the time Renault acquired majority ownership of AMC, U.S. major defense contractors couldn't be foreign owned and AM General was the result which had its own ties with GM using the 6.2 and 6.5 diesel engines originally designed when Detroit Diesel was still part of GM and GM sold a Hummer line for a few years before bad things happened with the economy.
It sounds like you have retired and I hope that you are enjoying it!