I'm tempted to jump on the bandwagon regarding scuba divers, but I think not all of their lack of SA is their fault.
When I got my first scuba tank at age 15 in 1954, I had already been freediving seriously and shooting fish bigger than I was for a couple of years. I was already completely at ease with the ocean environment, and the tank just permitted me to relax and enjoy it at a different level. I think my situation was typical for that era. After all, there were no certification courses, and my only instruction was reading the little owner's manual that said I should not hold my breath while ascending, along with reading "The Silent World."
In contrast, many, if not most, new scuba divers now have little or no experience in the ocean, are afraid of what they might see, and are not even very good swimmers. Its no wonder that they are focused on just breathing in and out and surviving.
My first scuba dive consisted of jumping off my father's charter boat in 25 feet of water with my speargun. After marveling over the fact that I could breath under water and verifying that it was true, I went after that big redfish that was hovering on the edge of visability. It was the same old environment that I had been growing up in, but now I had new capabilities.
Contrast that with the typical new scuba diver today. Last month he tried rock climbing, and now its time to check out scuba diving. There is a certification course, but its dedicated more toward getting him through so that he can buy equipment from the same shop that sold him the course rather than making sure he complies with rigorous standards. Some survivors of this system will turn out to be competent, safe, divers. Many will realize that they are in over their heads (no pun intended) and become a source for cheap barely-used equipment, and others will wander over the bottom not even noticing the freediver who is trying to point out things around them.
Sorry if I seem cynical about certification, but its a result of my personal experience. While I was a Marine officer, I went though a month-long US Navy scuba course at Pearl Harbor in 1962. People were actually permitted to fail, and the instructors didn't have any equipment for sale and only wanted to ensure that I was competent. But at the end of that tour when I was stationed in Caifornia at the start of the certification movement, shops wouldn't accept that Navy course before filling my tanks. They seemed to want to sell me a course first. Was there a conflict of interest? Am I a cynic? You bet your ass.
Later, even though I had taught her to dive before I married her, my wife insisted on going through a certification course. I watched the final pool session, and she was the only one who was even physically capable of swimming the laps around the pool on the surface while wearing her scuba gear. I watched my 12-year-old son do the same thing a couple of years ago, and it confirmed my opinion. I would not have been willing to go diving with any of the other graduates.
Sorry for the ramble, but I think scuba divers are victims of the system. I don't know about other countries, but in the US, the same people who run the course have an interest in the students passing. If there was a high failure rate, then the word would get out and they wouldn't get any students and they wouldn't get any graduates to buy equipment from them.
I returned to freediving at age 57 in 1996. Those tanks got too heavy to don anyway.
