Anecdotal evidence and a single data point.........so ignore this as anything but an illustration of what I have been saying in this thread.
I was out for a ride this morning when I was passed on the flat by a guy I'd guess to be 25 years younger than me, not carrying an ounce of flab, and looking like a seriously honed cyclist riding this years Specialised Tarmac. I was doing about 18 as he sailed by, and I thought nothing of it. I caught glimpses of him over the next mile or so as he opened up a lead of 300/ 400 metres, all on the flat, and I made no attempt to catch him as he was obviously way quicker than me, probably on a Strava-based mission.
I passed him on the next hill. It wasn't a massive hill, either, but he was fighting up it, standing up on his pedals rocking from side to side, and in a high gear. I sat down and spun a low one, and made up the entire gap in the course of the 800-ish metres. The thing is, I am sure he would justify his awful technique as "it's what suits me", but I'd be certain that he hasn't tried doing it any other way. With all his assets he should have been way quicker than me up that hill. He did say say "How the **** did you do that?" as I passed him, but I couldn't stop to explain as I turned off at the top of the hill, and he carried straight on.