I can't vouch for the historiography, but Top Gear's account of why Saab went wrong is worth watching.
"At one point, a GM accountant went over to Sweden to see why Saab was costing them so much money. And he got into the new 9-3, turned on the satnav, and thought "Wait a minute. That's not one of our systems." And he was right; it wasn't. Saab had developed -- at vast expense -- their own system because they thought GM's wasn't good enough."
"At one point, a GM accountant went over to Sweden to see why Saab was costing them so much money. And he got into the new 9-3, turned on the satnav, and thought "Wait a minute. That's not one of our systems." And he was right; it wasn't. Saab had developed -- at vast expense -- their own system because they thought GM's wasn't good enough."
https://www.youtube.com/watch?v=-iBgVUDUdqE