As far as the evolution thingie goes... I imagine there's several tons of people who've replaced jackets with jackets, back inflates with back inflates and etc.
The sad fact is most divers don't remain in the sport very long. Retention is a major problem for scuba. Most divers never replace their gear, BC included, because they abandoned the activity.
Those that continue to dive long enough to either out grow, or wear out their first BC, and purchase a 2nd BC are a small subset of divers. It is this group that tends to "evolve"
Yet in the places where I dive, one sees very few bp/w's. That doesn't mean those people don't replace their bc from time-to-time but it sure indicates the style of bc they buy.
We had this very debate many, many, many, times before.
The "percentage in use, or percentage sold" argument is pretty weak.
The fact that jackets / vest etc. out number BP&W's 100:1 or 1000:1 says nothing about the relative fitness of either design.
There are so many other factors that impact the % of each type sold or in use, not the least of which is distribution.
Do you not find it telling that in the last 3-4 years there have been 3-4 major new entries into the BP&W market? Hollis, Apex, XSScuba, Edge / Hog and probably a few more I missed? I wonder what they know that you don't?
For the warm water wusses out there who are perfectly happy diving in clear water with single tanks a bp is about as needed as a hole in the head.
Don, I'm happy you enjoy diving whatever way you choose, but I have many 100's of happy customers who prefer their BP&W for warm, clear tropical diving.
Tobin