Originally Posted by kbarch

No.
There are a number of ways energy can be expended on the bike without getting it to the wheel. The most extreme example maybe something like jumping up and down while doing a track stand. I'm sure you can imagine a number of other ways our feet can apply force to the pedal where the resistance comes from the structure of the divetrain itself rather than the road or the air. I'd suggest that rollers are inherently unforgiving of the kind of pedaling form that wastes energy and upsets equilibrium that way.
I don't know anything about the absolute magnitude of the energy losses inherent in poor form, but riding rollers teaches one that they are not negligible.