Not sure where this kind of stuff really belongs on these forums, but there should be a place for it here somewhere.
As for GM… I think they have a long history of being their own worst enemy, with lots of squabbling between different personalities, divisions and factions. We saw that with the EV-1, when different parts of GM were simultaneously trying to make it a success and kill it.
And then there's the C3 Corvette "Stingray". In my humble opinion it's the most beautiful, sexiest, coolest looking car in history. It was a sensation when introduced, and even today the look has never grown old. It doesn't look like it came from the same world as other 1960s cars. However… GM stole the design—from themselves! The Pontiac Banshee prototype was developed first, then GM management decreed that Pontiac couldn't be allowed to upstage the Corvette, so they killed the Banshee and then had Chevrolet develop their own Banshee-like Stingray.
We must be careful when talking about supercars, because it's one of those terms that can mean whatever somebody wants it to mean. (And hypercar seems to be based on a single criteria: money.)
The original Tesla Roadster was touted as a "supercar" by Tesla, but I don't think a lot of people took that declaration at face value. And if you are a sports car purist, the Roadster doesn't count as a sports car because they aren't generally raced and they aren't suitable for track use.