Having managed a dive shop for awhile, I have to agree with MikeFerrera.
The equipment manufacturers dictate terms of sale, etc., while the training agencies do the same for certifications.
If LDS's are relegated to training and fills (and let's not forget servicing gear), get ready for a real downswing in the ability for divers to get certified. Think about it-how much do you think anyone would have to charge to keep a shop going on this? Let's face it, unless we all want to go back to a "Ma-&-Pa" arrangement working out people's garages, then the system of equipment and stores will have to change.
The brick and mortar stores will have to change to compete with on-line sales, but does anyone here remember the same crisis mentality with catalog sales of equipment? The doomsayers cried that the retail sky was falling then too. What this all means is that shop owners with no business skills will be filtered out - law of the economic jungle. Those that have enough business savvy to stay afloat will, even competing with the on line places.
As with everything, there will be a new balance. Some shops will go, some on line providers will go. Some goods/services will become primarily on line, others will tend toward the shops.
And I now dismount the ol' soap box for some else to have their turn...