thats because american cars arent aiming to make big power out of V6’s like the Japs are. Thats what they make the V8’s for. The 505hp C6 Z06, the 640hp Zr-1. 660hp Viper, 550hp GT 500. 390hp Cobra, Saleen mustangs, Roush stangs, Ford GT’s… I could go on all day…
American V6’s made big power in the 80’s (the GNX, grand nationals, turbo trans am) then any import V6 in that era and are still holding their own to this day.
The camaro IS a performance car to the people who like them and want to be different from a Vette and save money in their pockets. They have the same power plant as a C6 but are 20k cheaper.