And still Eddy Merckx did his one hour record on a ultra flexible frame, and light btw, but he was cycling on flat indoor race track.
Once my friend asked me, if I can give him my new aero wheels (flat spokes, v-shaped rim). After the race he told me, he pushed harder, because of the better wheel. Some weeks later the wheels among others were mearsured by a German university. They had the highest drag and was among the heaviest.
But they look good, I still use them. It is the placebo effect who counts more than 100gr and 1 or 2 drag counts. It is all about believing like religion.