Usually, the price spread on a given model is maybe $10,000, or so, at least on "normal" cars, and you start to add usuable functional items, or at least convenience items. We got the top of the line Hyundai because the hybrid piece has more horsepower, and my wife wanted cooled seats (which i didn't care about, but they actually work pretty well).
I know Porsches have a very large price spread, so it's not unique for Corvette.
I don't think I'd want a 1,000 hp Corvette even if I could afford it. I might like a Z06 because the exhaust note is so different.
If I wanted a Cadillac Blackwing, I'd get the smaller CT4 instead of the CT5. I kinda do want one, with a manual.