Happened because the geniuses at GM (the same ones who gave us Herb Fishel) decided that GM should be like the Borg. All GM cars should be identical to their sister cars in other divisions.
Then they decided to abandon the market that Oldsmobile catered to.
The Oldsmobile buyer was the person who wanted a medium to large semi luxury car with a V8 and rear wheel drive. The Olds 88 and 98 ceased to fit their needs and desires back in the mid eighties. Throughout the eighties, the number one car in the U.S. was the GM G body (Cutlass, Monte Carlo, Regal, and Grand Prix). Number one was the Olds Cutlass. When production ceased in 1988, 3 years after GM wanted it to, the Olds Cutlass was still a top seller. Once they killed the full size V8 rear wheel drive 98/88 and the mid sized V8 rear wheel drive Cutlass, Oldsmobile was doomed.
GM COULD have done a redesign, and built the full frame rear wheel drive cars with aluminum frames and engines, and lightened them up even more, added fuel injection and better computer management for high performance, excellent fuel economy, and low emissions. But they took the cheap way out and screwed the pooch. And the customer.
Rather than build the cars that people WANTED, GM, like the liberal left, decided to build what they thought people should buy and have, and attempted to force them on the public. Lo and behold, sales dropped like a stone. Turns out "we know what's best for you and what you should have" is NOT the way to sell mass quantities of product.
The death of the V8 powered rear wheel drive car, whether full size like the Impala or intermediate like the Monte Carlo, is exactly what drives the mass movement to pick up trucks and SUV class vehicles. The entrance of the minivan caused the death of the large rear wheel drive V8 powered station wagon, again making the SUV a bigger seller.
Being a former mechanic, I can tell you I wouldn't have a minivan if you gave me three. I despise those stamped sheetmetal underpowered front wheel drive flimsy trash cans.
The identity crisis at GM continues. There is no pony car, so they surrender that market to the Mustang, despite the fact that the last F body cars produced were light years ahead of the Mustang. There is no full size V8 rear wheel drive car, so they surrender that market, including the police pursuit cruiser segment (all of whom dearly loved the police version of the Impala SS, which ran and drive circles around Ford's Crown Vic) to Ford. As such, they also give up not only the Chevrolet sales in that market, but also the Buick and Oldsmobile sales as well.
When you charge in excess of $30K for your product, you better make it what people WANT, not what YOU think they should have. The only thing saving GM is the truck divisions and their size. The stupidity runs rampant. If they kill the S-10/S-15 in order to sell only the Colorado/Canyon, they'll lose that market as well.
I am a diehard GM kind guy. I own a 1964 Chevy C-10, a 1965 Chevy Corvair Corsa, a 1970 Chevy C-30 (now a K-30 4X4), a 1981 C-30 Crew Cab Dooley, a 1983 Cutlass Supreme (with a 500 HP 455 4 wheel disc brakes and a narrowed 4.11 posi 12 bolt), a 1984 TType Regal (turbo V6), and a 1998 Firebird.
I'd LIKE to have a new truck to replace the old 1981 junker, but $37K is more than I can afford.