In 1970 GM top brass felt the need to disperse operations (created GMAD - General Motors Assembly Division) because the fed was making noise about GM dominating the market (over 50% market share in the 60's AFAIR) and some wanted to break it up. Ten years later mostly the same people were at the top and the mavericks (e.g John the Z) had mostly been driven out. While at GMI I also met many of the "more inventive" engineers like Bill Collins and Herb Adams (Bill later invited me to join the Vixen team but I liked playing with F-16s and F-111s)).
Frankly have always thought that GM in the 80s was dominated by bean counters with little imagination. Remember a late quote that the reason GM kept building large cars so late was because that is where the profit was. Never understood Ralph William's motto.
In the mid-80s each division was allowed to design/build a "halo" car to match the Corvette: Pontiac - Fiero, Buick- Reatta, Cadillac - Allante https://snaptube.cam/ 9apps, Oldsmobile - Bravada (1990). but all of them were too little, too late, and too expensive. (in 1984 Market was all minivans & did not understand a SUV - the Bravada).
One issue was that the general did not understand that a sporty car needs to be able to get out of its own way. Except for the Corvette, all had less than 240 lb-ft of torque on introduction and all were criticized for being slow. Death for a sporty car.
Unfortunately the Cimarron came along at about the same time and while a two door "J-11" version witha V-6 and a five speed could have been easy (same emissions class as a Cavalier). it didn't happen and the result could be easily predicted...except by accountants.
Personally put the breakover from "slow" to "OK" at 270 lb-ft and quick is over 300 lb-ft in a 3000-3500 lb car. Under 3,000 lbs over 200 lb-ft is OK. (something about "you can sell an old man a young mans car...")
Result: all lost money. GM expected 20,000 per year. Only Fiero hit that point but also only one available with a manual transmission & was gone in 1988. Most "got it right" just before being cancelled.
Then Oldsmobile went away and a prediction of the future when GM eliminated Saturn, Saab, and Pointiac (Chinese liked Buicks)
Today GM's market share is about 17%. Its sad.