Cars do get better gas mileage then 30 years ago, and it’s absurd to think otherwise. A typical late-70’s GM V8 car was getting about 10-12 mpg. Additionally cars pollute much less today, and have hugely better performance, so perhaps your “mileage is about the same” isn’t quite apples-to-apples.
Engine performance improvements have largely gone towards HP and torque, and not MPG, because that sells cars. If you don’t believe me, go look at 0-60 times for the average car then, versus now.
And you still fail Logic 101. There is never a burden to prove a negative, which you are still demanding.
We can knock a missile out of the sky with another missile now. They laughed at Reagan and said it can't be done. I say there aint no reason why we can't have better gas mileage then we have.
I am not going to insult your intelligence by pointing out that Logic 101 says, if you really try you get better results.