DCB, fair enough, I agree with you on that.
For me personally, my 9 mile commute to work kept me in that efficiency zone the vast majority of the time, so it worked well for me.
Anyways, if anyone reading this hasn't tried a fixed gear, see if you can find one just to try. It is fun to discover the efficiency gain, even if it is a trade-off of efficiency at other times by not having gears.