Yes. And I'd say computerized fuel injection caused a great improvement in combustion efficiency. Others would probably include improvements in cylinder head design, intake/exhaust tracts, turbos/supers chargers, etc.
I think you've hit the big ones here. Fuel control, timing control, variable cams, cylinder deactivation, not to mention much more efficient transmissions...newer tech (that grew from our classics) really has created some incredible efficiency and power.
Fuel control is the big one. It allows some amazing applications of high compression or boost, each of which allow us to get a lot more energy out of our gasoline, specifically sending less of that energy into the air as heat and using more of it to propel the car...which directly means better MPG.
Take a look at the Mazda Skyactiv engines. The 2.0L in the new Miata has 12:1 compression! At one time, this was reserved for very special cars and race applications.
