These old cars can be a lot of fun but even the fast ones weren't that fast when taken against a modern family car... take a 68 Mustang, an iconic car as featured in Bullitt, with a 0-60 of 5.4 seconds and compare it to a 2012 Toyota Camry doing the same in 5.8 seconds.
Here's the thing. A 68 Mustang had no almost emissions controls. A 78 Thunderbird was almost the exact same stuff, except it was choked to shit. A modern computer-controlled Camry is not only way better performing, it also orders of magnitude cleaner.
IMO the ICE has achieved its final form, so now the future has to be something else (electric).
It's an intersting time to live, we are indeed seeing the peak of ICE, though I think there are lots of room for improvement in EGR, compression, more efficient catalytic process.
"smaller market" ICE manufacturers IE isuzu, mazda, hino etc. are sort of working towards this, as opposed to jumping on EV train.
Theoretically, it's completely reasonable for a high compression inlne 3 cylinder with aero wheels/tires to get 60-70 MPG. (With proper EGR, turbo application, CVT)
50mpg from a 5.7L V8, using most of the drivetrain from a truck(!)
My daily driver gets roughly half that, but it has a carbureted 6.6L and an automatic transmission, with some mild performance tuning done. I am satisfied enough with that.
