Wow- very interesting questions raised here and so many different ways to look at it.
And any real answers would run to book-length. Which, eventually, it should, 'cos in my opinion there has been too much attempting to do what the pedestrians do and not what we can do and they can't.
A few points, however, not all of which are central to this:
Let's distinguish between rail turns and what I'll call 'pivoting' or 'torque turns. The pedestrians have it all over us there, as they have more ability to pivot their bodies and redirect around a point, just 'cos of basic mechanics. If, for instance, I can pivot my upper body 30 degrees, they can ( not saying that they do ) pivot 90 degrees and pivot everything from the ankles up.
Likewise compressing and extending on a drop or a turn - they have the same body mass but more vertical distance to use in that compression-extension move. They can exert the force and do more work ( W=F*x) to crank themselves out of a turn.
Trimming, they are way ahead.
Of course, 95%+ of them don't, or their equipment holds them back. The average standup is going with the herd.
Also, we tend to be more technologically aware than they are, and think more about not only the 'athletic' aspects of what we are doing but the physics of it all.
For that matter, the average kneeboarder has tried 'regular surfing' and found it wanting from a performance standpoint. 'Cruising' doesn't appeal, going flat out and driving hard through turns does. Let alone being well out in front of the vertical sections and doing flashy tricks.
One picture comes to mind as a good example. A downhill skiing race (Olympics?) quite a while back and a guy called Franz Klammer. Everybody else was going along in their nice little tuck positions doing cookie cutter moves one just like the last....and then along comes Klammer, flat out and on the ragged edge, barely in control. And he took it, his time was better than theirs.
Similarly, take the paradigm shifts in surfing as a whole. You have the 1970 era standups posing, doing stupid surf tricks on the nose ( the quasimodos, the hanging five or ten) , and that's as good as it got. Non-functional. And then along comes a guy called Greenough, flat out down the line and powering. Guy called Lis, working the vertical, not the flashy, splashy turns, tucked high and tight and it makes a lousy magazine cover on account of you can't necessarily see him from the beach.
they saw what
we were doing and attempted to copy it. Very few realised that we're doing something more advanced and while it might not be as flashy, might not impress the contest judges or make a splashy spray-throwing photo for a magazine, it works.
We're dealing with a whole different range of speed and stall speed. We can't slow down and then use body moves to get us back, we have to be flat out in the pocket all the time. One of us does a cutback, it's not way out on the shoulder, it's in close, slam it and stay in where the vertical gives us speed.
Look at a standup's wave versus a wave optimal for kneeboards. If it's not hollow, fast and vertical, we don't really want it.
As Harry puts it so well -
But when you stand up you are just one of the million trillion faceless masses who aren't necessarily surfers but bankers and clerks and builders and fireman who are merely "having a surf."
But we're taking on the beast.
doc...
. Kneeboarders are the centaur's of the surfing world. Not half man and half beast, but half man and half board. Not standing atop, and riding a board, but being one with a board riding a wave. 
