What you need to realize is that what WE want, isn't gonna be the same as what most of America wants. For example, the Trans Am was a modern muscle car. It was a beautiful, badassed looking car, that performed better than the Mustang GT. However, the Trans Am, and even the base model Firebird, were canned, because they weren't selling enough. Hell, the Mustang outsold the Firebird and Camaro lines COMBINED in their final years of production.
And when you look at the Mustang, the vast majority of Mustangs sold, are not the GT models, but the base model V-6s.
If you make a modern, no-frills, stripped down performance car (ala 68 Roadrunner), ALMOST NOBODY WILL BUY IT, because today's people are spoiled. People want their electric 6 way seats, their air conditioning, their navigation systems, their in dash 6 CD player. The Viper was an exception to this, but that's because the Viper is America's "Super"car, marketed to the Ferrari-buying crowd.
The type of car that sold well 40 years ago is not going to sell well today, because 40 years have passed, and the wants of the average car buying consumer have changed. Buyers now look at gas milage, at safety, at how much it can haul, rather than at how fast it goes, or how big the engine is.