I'll take a shot at this with the way DIR ( for ocean) came to us in South florida
....I had been spearfishing the Hole in the Wall with Frank hammett for years, along with dozens of little known barges and wrecks between 112 feet deep, and 175 feet deep, mostly from Juno to Fort Pierce. I dove with the serious hunters that liked Frank hammett's trips, and the level of adventure his trips represented ( in stark contrast to the typical charter boats that would cater to novices, and ruin diving for advanced divers).
So I met George diving on the HydroAtlantic, on a day with lots of Greys running, and huge walls of fish. George was way more techy than the other hunters ( double tanks), but beyond that, he was just a really good diver, and he fit in well diving with any of my normal hunting groups. We tended toward buddy diving even before George, as we were diving in places with lots of big bulls that would come in while you were trying to pull your grouper out of a hole, and it was wise to have a buddy there to persuade the bulls not to "help" you pull the grouper out of the hole
We also had a great many small relatively unknown and undived wrecks we would hit, often sitting in big currents, and typically with plenty of entanglement challenges....and covered with big fish. Buddy based spearfishing just made sense here, and it made the stories more fun after the dives.
After a year or so, George dissappeared from the weekly dives----and we did not see him again for almost a year...then one weekend, he was back, wearing new gear...backplate and wings, long hose, and even though in doubles, he was remarkably streamlined and fast in the water.
We did one of the deeper wrecks, looking for fish, and inside the inner compartments, George blew our minds with the "way" he was doing things none of us could do. He was motionless and effortless in places some of us could not even get into, and even though all of us were great in big currents, we could see he had something that was a huge advantage over the rest of us....and we all wanted these secrets...we could all see the value in being able to do what George was doing..how we could get fish that would have been out of reach before, how we could be safer without effort, much less prone to getting tangled up, and how we could have even bigger adventure dives, with far less effort.
George told us about the cave diving with Parker Turner, and we heard about Scheck, and we basically came to realize there was a kind of diving going on in North Florida that was MUCH harder than what we were doing in the ocean...but that these guys who were doing it, had evolved skills ( skills we could learn) ...that could make each of us MUCH BETTER in the ocean. We could see how the gear George was using was superior for what we were trying to do..and it only made sense to try this stuff...we saw how dramatically it had amped up George's game, and we wanted to see what it could do for us. George would say he began the cave diving, to make himself way better for deep ocean diving, but in time, he came to like the deep cave as much as the high challenge ocean diving. But let me repeat this again....
George said he was doing the technical cave diving with Parker, in order to be better at the challenging ocean dives we did, and to enjoy them more....So the DIR we were ultimately to put out over years to follow, was VERY MUCH about diving in the ocean...
George would go up to Wakulla and miss a few weekends doing big cave dives, then he would be back sharing new ideas and new gear set ups.
Bottom line, the whole DIR beginning for us, was about giving you some tools to do the coolest dives you could find, safer, and better. We had some pretty outrageous dives in depths less than 140 feet...so it is not fair to say this was specifically a technical diving development....those of us that liked the really deep shipwrecks and reefs in the 220 to 280 foot range, knew we would be stupid not to use George's ideas....but many of the group that just did dives like the Hole in the Wall, the Rolls off of Juno, and some of Franks secret spots, liked this new development for the advantages it gave us.
Of course, this is not reading about an idea, and intellectualizing about it's value....
....this was you seeing a huge change for the better , and wanting this, and more. This was all hands on, see how it works, ask the whys, and then adopt it after you are certain this is hot stuff.
For the more general question of how would DIR evolve that you suggested, I think that if it was just Grand Cayman style "bath tub diving", protected by divemasters, then there would have been zero development for DIR. It needs to be in a place where you have big currents, big challenges with potential entanglements and divers trying to push the "recreational envelope". Ideas such as the long hose and 2 or 3 man buddy teams should have "co-evolved", whereever real challenges like we have exist. Whereever you have big currents, and you also want to maximize bottomtime ( minimize wasting air), the backplate and wing set up is going to be superior for it's low drag. It was amazing to me how many of the cave diving skills, had spectacular application to our more challenging south Florida dives. As soon as you find you are in a place where true buddy diving makes the adventure safer and better, then it is fairly obvious that it is better if all buddies have close to identical gear, so in the case of a failure, fixing the issue is far simpler from the familiarity.
As other posters have mentioned, a typical scuba diver is going out on a charter boat, and diving where little if any challenge exists... and where mistake after mistake are commonplace for these dive groups, and yet the fatality rate is incredibly low. DIR ideas will require more challenge to make their advantage worthwhile to most divers.
Sorry if this went on too long
Regards,
Dan
