No matter how much we "market" scuba, in the end it can never compete with rock climbing, yoga or any of those activities you rightfully mentioned. In the end we have to realize that this will never be "recreation of the masses" like Zumba and just like marathons and triathlons attract thousands, scuba never will. It will only attract a small and dedicated community of explorer types and I suggest it is best if we keep it that way.
I never said scuba should/would "compete" with those things. I was raising them as a possible clue/insight into the psyche of today's consumer. What is it about those things that appeals to people. What does that tell us about them, and how might scuba latch onto that for a marketing edge?
As far as triathlons attracting thousands... there is far more training, work, and even cost involved in participating in even recreational triathlons. Hell, the wheels alone on my bike cost $2000.
You talk about a "dedicated community of explorer types" and "suggest it is best if we keep it that way." That's a lovely thought, but don't let the way you'd like the world to see you cloud what the world might actually want to see in scuba diving. Bear in mind, this discussion is about what the scuba industry can do to help itself grow and expand. It's not about how current customers can hold on to some irrationally romanticized opinion of themselves. Hell, I'd bet that part of the problem the scuba "industry" faces is that it misguidedly zigged down the "adventure/explorer" route when it should have zagged down the "serenely commune with nature" route.
Ironically, I would even make the case that the "serenely commune with nature" positioning would be more strategically consistent with better trained, more aware divers than swashbuckling underwater adventurers? How often do we hear people talk about "zen" of diving. Being "green" and not wasteful, and embracing minimalism (think barefoot running shoes, etc) would be consistent with minimalist HOG/GUE type diving. Whereas the underwater Indiana Jones/James Bond would be far more desirous of buckles and retractors and excess and the like.