[bluGill]

According to physics an ICE is most fuel efficient at 90% throttle and low RPM. At high RPM, or lower throttle positions you lose efficiency. So if you want maximum fuel efficiency you need to put the throttle to the floor, but stay at low RPMs. Thus the CVT is not doing the right thing for fuel efficiency. (though I'm not sure if the difference is worth measuring)

Obviously the exact numbers varies a bit from engine to engine.

[wtallis]

When you put the pedal to the floor, you're not trying for efficiency, you're trying for power.

Dropping to lower RPM for efficiency is what happens when you're done accelerating and ease up on the pedal. That's not what people complain about with CVTs. The complaints are about behavior and sound during acceleration, not after acceleration when you are merely cruising on low power output.

[bluGill]

That might be you, but not me. I'm always trying for effiency. My cars never have the acceleration to make power interesting. I'm weird, but whatever.