>>An independent will bounce every dollar (pound, yen, franc, mark) around about six time before it leaves your town; a chain will bounce it around the local economy about 4.3 times.<<

This is not true.

If the one dollar book cost the store 60 cents then that 60 cents will go to the distributor unless the distributor is local then his cost of goods sold will go out of town, likewise any other direct selling expense from a vendor associated with the sale of the book will go out of town. Now the money you spend in the coffee shop of your bookstore will get spread in your local area.

Because of volume and reduced costs Amazon is probably selling at close to the local, small bookstore's cost. If you want to help the local economy? Buy Amazon, spend the money you save on local services.