Price is not the only differentiator. I'm a relative newcomer, but what I see as the achillies heel of the LDS is that for years they have relied on just being there to generate business. It didn't matter what they sold or what they charged, they were the Local dive shop, or the shop where you did your training and you would buy from them. This is the model that AL is trying to perpetuate. "You will buy or prodcuts at the LDS because you have to." For years, many shops relied on what was essentially a local monopoly. By definition, monopolies don't behave in the best interest of the consumers, so when other options come along, consumers flee.
If the LDS wants to survive, they can do so simply. Provide services that can't be gotten elsewhere. Do what they are good at. Be local, provide one on one service. Training, air, help to new divers. Prices will have to go down, but they won't ever need to match online. People expect to pay more at B&M stores, and they are willing to, within reason. But extortion won't do it.