I may be able to help with this question. What follows is conjecture based on my knowledge of typical dive shops in the U.S.
I don't know what it is like in Australia, but here in the United States, industry statistics indicate that fewer than 1% of all BCDs sold are BP/Ws. Although I don't have the facts to support it, my suspicion is that most of that 1% happens in 3-4 states. True technical diving occurs in only a tiny subset of the entire diving population--it just seems like its the majority here on ScubaBoard.
I think I had completed 200 or more dives all around the world, including Australia, before I saw my first BP/W. I believe I still have seen fewer than 20 total in resort areas around the world, and all but 2 of them were on the backs of people I was diving with after contacting them on ScubaBoard. The shop with which I am associated sells BP/Ws and other tech equipment, and it has people on staff who can give you good advice, but that was not true 5 years ago. If you had walked into the store then, you would almost certainly have been directed to a jacket style BCD by an extremely experienced diver/employee who had never seen a BP/W and who had only a vague notion of what technical diving entails. Those employees might have recommended precisely the same package that was recommended to you, not having any idea that it was bad advice.
These employees might have very different definitions of "deep" and "wrecks" that you do. If you are talking about popular wrecks like the Yongala, they can be dived easily with any BCD, including a jacket style. Most of the wrecks people dive around the world can be dived with recreational gear. It is only when you want to get into a higher level of wreck diving that the special equipment and special training become necessary.
They also might not normally sell BP/Ws for very good economic reasons. They are simply not good sellers in most areas, and in most cases the shops would lose money carrying such an inventory, especially if they had to make a deal to become a distributor for a company that specializes in tech equipment. Those companies often have minimum sales requirements that most shops have no hope of reaching. In your case, the shop can sell you a BP/W, but they might not realize it because it happens so rarely. If they have the ability to sell you a Cobra, then they have the ability to sell you an Apex BP/W (same parent company).
