4) That divers feel better after their conversion to a BP/W can come from many reasons, including placebo/self-suggestion. It can also come from a better trim, and it seems to often be the case, especially for divers who use quite a lot of lead.
So that's the full version of what I wrote, Tobin George, and it's not all about brain-washing as you seem to believe. By the way, self-suggestion doesn't need any brain-washing : everybody, me included, is very reluctant to admit that equipment or vacations that costed a lot is crap or even average (no pun to BP/Ws intended here), so there is a cognitive bias with pricey stuff.
I, at least, tried to be factual.
Most new buyers of a decent BP/W setup will have no reason to become bitterly disappointed with it (I know some exceptions, mostly experienced DMs or instructors who have found that they didn't get as much from their BP/W as what was advertised ; but they don't care about Scubaboard). This setup will do the job, most probably, and often will do the job well.
For single-tank diving in tropical/temperate waters, good jacket BCDs would have led to similar results in many cases. But not all models of jacket BCDs on the market are good ones ; they often need to be "trimmed" ; they don't fit large divers as well as BP/Ws do ; they are less "stylish".
On the other hand, the best jacket BCDs (like Scubapro Classic Sport) are homologated in Europe as "life-savers" on the surface, they provide excellent balance underwater in any position, and they are very streamlined.
I understand that marketing/advertising has to be done, yet good BP/Ws have enough genuine assets (eg simplicity, modularity, robustness, adjustability and snug fit, uncluttered torso, fully available lift, comfort on one's back ...) to not insist heavily on more "questionable" (to be polite) ones (eg drag, ease of venting).
The readers of this thread will judge by themselves. Cheers.