From The Truth About Cars. GM senior management had brains made of solid concrete. Buying into SAAB was a dumb idea in the first place, and running it at a loss for 8 years is even dumber. SAAB made an interesting niche car that had a loyal fan base. But you can't make money on niche cars. They don't have the sale volume to afford the mass production tooling needed to get the cost down to compete with real volume makers like Toyota. If they reduce costs by replacing expensive handmade European engines (and other items) with nice cheap dependable Detroit production line V-8's the loyal fan base stops buying, insulted by the presence of mass produced Detroit iron in their beloved European hot rods. It's a no win situation for a US company buying a European luxury maker. If US management had been real car people they would have understood this and saved their money. But at GM senior management is all bean counters and MBA's.
Ford made the same mistake getting mixed up with Jaguar. But Ford brought in a savvy CEO (Mullaly from Boeing). He figured out that Jaguar and Volvo were losers and was able to sell them back before Great Depression II made raising money for takeovers impossible.