Welcome to SB!
I don’t think it is reasonable to expect your local shop to have everything you want in stock, even if it is a major internet player.
My shop has a philosophy of diving what it sells. The selection in house is deliberately limited so that it can keep the stock available and prices competitive (lower than online) due to the larger volumes they sell. They will normally suggest a Backplate and Wing setup for anyone buying gear unless of course your requirements don’t suggest so. There won’t be every brand of BCD or regulator on the market, but there will be stock on their go-to Apeks regs. It would be the least I’d expect, and would be surprised if they were out.
I don’t care if you bought your gear beforehand. I did buy my entire set after less than a dozen dives and in cold water, that is definitely a $5K+ investment. However, I got lots of good advice on what I needed locally, hence I ended up with a BP/W that I’ve gotten huge benefit from. I wouldn’t necessarily have even known about them if I hadn’t talked to the shop.
I do have to ask whether you had made a list of items you wanted to purchase that they weren’t able to fulfill (and hence your rant here), or if they steered you towards the brands they stocked (e.g, towards the Air 2 inflator)? It seems like you bought some items online as well? How did you create that list as an unexperienced diver?
My point is really for you to understand your shop’s motivations and what sort of relationship they build with customers. Are they just there to sell you stuff, or to meet your long term needs? With experience as a diver, fellow dive buddies, and the collective wisdom online, you’ll start to refine your BS radar. As others have harped on the Air 2, it to me isn’t pointing to a concern with the device itself, but the shop’s intentions and philosophy (for both gear and training).
As to high-end gear, I consider a shop that rents out BP/W systems to do high-end gear. Not ones that have jacket BCDs with tons of pockets, D-rings, and other crap. A good BP/W setup that’s a pleasure to dive with is often less than a high-end jacket BCD.
In the end, it’s just money. Many (all?) of us have bought items that we quickly outgrew and regret the purchase of, even if it seemed like a good idea, was recommended by others, and thoroughly researched beforehand. Luckily, stuff generally works fine and won’t try to kill you. But getting to that place of equipment bliss and diving pleasure can be smooth or twisted. Best wishes in your training, enjoy your purchases, and make sure they make you want to keep diving.