One thing to keep in mind is that often when you see vacant storefronts, what is actually happening is that the owner of the building is redeveloping it. Businesses have multi-year leases. If you want to redevelop a commercial building, you have to either pay a fortune to buy everyone out of their leases or slowly wait a few years for the building to empty out.

You might ask why they don't offer month-to-month leases in the meantime, but there's little demand for that. If a bank is lending you money to start a restaurant, they want to see a long-term lease agreement. They're not going to lend you hundreds of thousands of dollars to purchase and install a restaurant's worth of equipment in a place with a month-to-month lease. There are very few businesses that would be interested in such short-term leases. And the few that are willing aren't worth the effort for the pennies that you could get out of them. The only real rental customers for buildings that are slowly being emptied are seasonal retailers like Halloween stores.