In diving I have no need to dive like a SEAL, they are on a mission to get a job done, I am not, I am there to enjoy the dive not race through it so I have little to no need for a fin that is marginally faster than what I wear. I like the feed back in the fins I use because I can control exactly where I want to be in the water column, up tight against a wall observing the little things, backing up and all the things that feed back gives me. I like to be able to put the brakes on at will with my blades and feel the water resistance stopping me. With FF's I did not get that. It was harder to judge my speed, stopping and turning. When I did dive the FF's I found myself always way ahead of way behind the other divers constantly having to think about over finning or not finning enough because I couldn't feel them and how they react to the water around them. Are they easy on the legs? yes. Can they be the best fin for SEAL divers, I suppose they could. Are they for everyone, no and no amount of defending them or studies or proof is going to change many peoples minds. There is no such thing as best for all people no matter how much research you do to prove otherwsie. If that was the case we would all drive Camry's.
What FF's lack to become main stream is marketing. Trying to force a product down someones throat with the techniques used by the hard core FF wearers will never ever work. If anything it will drive people away. Like I said I own them and know a few others that own them and don't use them so I doubt the 99% comment.