Oh boy, this looks fun,
About me first, so you know you can safely ignore me,
25 dive 10 in Maui, 15 in cold water.
I'll start with halemano's list and continue,
Most dives in water warmer than 70, for sure this is true, I know that lots os people dive lots in cools water, but I don't we can compete, with central America, Mexico, Egypt, thailand, Indonesia etc, this leads to the agreement on 5 mm wetsuit issue, and to me lends credence to the full foot fin issue. I didn't see many full foot fins in HI, when I was diving, but I wouldn't be surprised that they are common in warmer locals as they seem nice, I don't see myself using them, but what the heck. Jacket BC's again I'm on board, that is mostly what the shops here sell, and what was on the boat, from a lot of different locations, even the dm's wore jackets iirc. Hmm classes I have never seen a 3 day but 4 is common here, so this seems likely, I would say it is the padi norm, I just don't know how the durations of the other major orgs.
Now we get into more debate, having said I believe that most diving is done in destination I think it is possible that most dives are guided, and by guided, I mean with a dm in the water But I'm not familiar enough with the areas listed above to be sure. It seems That al80's aren't that common in other areas of the world but it is all you can rent around here, so I'll let others with more experience chime in.
And now onto disagreements deep in the first dozen nope, greater than their cert level yes, Caverns again nope, just aren't enough, overhead included maybe, but a dozen dives is pretty low.
The dive industry has certainly evolved to cater to this group above because even if they don't match the spend per person of a hard core diver, their spend overall will be higher plus you can get economies of scale. It would be too bad if people felt the dive industry didn't provide for them but I don't think that is the way, even for people who don't fall into the common areas above. They may wish there were more bp/w's available but that doesn't mean they aren't provided for.
Other thoughts on the world of diving, if you start before kids and don't dive locally you will stop when you have them. If you take your cert for one trip you will likely stop diving after that trip, happened to me once.
That is all I can think of for now.
Ben