You don't even need to go to this crazy extreme to find relatively modern levels of fuel efficiency. The classic 60s-era Mini could get ~40mpg with a plain old

You don't even need to go to this crazy extreme to find relatively modern levels of fuel efficiency. The classic 60s-era Mini could get ~40mpg with a plain old carburetor. As ICEs became more fuel efficient, the vehicles became both larger and heavier, negating the gains. Modern ICE vehicles have become so overweight they've managed to make EVs look somewhat average in the weight department.