I've only been diving 11 years in Ontario, but I don't see diving as dead, far from it. There are tonnes of divers diving in Ontario but the type of market has changed and the store owners need to change with it. Typical divers are more exposed to forums like this; have more knowledge of different types of diving, equipment, courses and techniques than they once used to; have the ability to shop around a lot more than they once did, and are part of a global economy more than ever before.
If shop owners continue to offer the same equipment, the same courses, and the same high prices that they did 20 years ago, they can expect to fall behind in this consumer's market where they are looking for the status quo in training, equipment and knowledge today at decent prices. The SCUBA travel market also seems to have increased substantially and many dive shops are offering more travel and more exotic travel through their own travel agencies. Many dive shops have also taken advantage of providing online shopping. Many dive shops also have an online social media presence through Facebook, Twitter, and scuba boards. Some dive shops sell their gas by volume rather than by fill or have loyalty cards where you get some fills free. Store owners who keep up with the long-term trends do seem to be doing well, rather than just staying afloat.