Well, one answer to this that has merit is simply supporting your local economy. Since many of us in the states live near large cities, the impact of this isn't as obvious, but in smaller towns, the local economy can be much less stable. Once it starts to fail, it can be hard to control and can have disastrous effects on those who live there.
Unfortunately, simply supporting your local economy will not help many dive stores. There are so many local dive stores in markets that are so small, all of the local support in the world will not help. Furthermore, almost all local, regional, and national "support your local community" program fail miserably. We are all consumers in a national or worldwide market. We will support local merchants when it is painless. We will not pay a premium to support a local merchant.
Important Note: If you don't believe this, how do you explain leisurepro, scuba.com, divers-direct, divers-supply, scubatoys, etc. It is simple. We will completely abandon a local merchant to save money.
Anyway, just my opinion.
Phil Ellis