Well, I bought a brand new 1972 Chevy Impala Custom Coupe in April of 1972, the week I got out of the Army. It got about 14 MPG.
Today I have a 2017 Chevy Impala and it gets 29-30 MPG.
If the 72 got 10,000 miles on a set of plugs, that was good. Ditto the points in the distributor. New cap, rotor condenser every 10,000 also.
If the tires made 10,000, that was also exceptional. Now they get 50,000 or more miles per set!
I dont even open the hood of the 2017 between oil changes— nothing to fix. It just runs and runs.
The 2017 has a catalytic converter and I’m pretty sure it emits a lot less pollution than the 72 did. Goes almost as fast, too.
My point is, yes, there were some hiccups in the mid seventies with electronic carbs and solid state ignitions, but we have since made tremendous progress in cleanliness and efficiency.