A lot of things can work at small scale that don't work at Radio Shack public company scale.

Example. There's a board game store in Harvard Square that has been there forever. I assume it must make enough money for its owners to have stayed in business all these years. That doesn't mean that opening hundreds or thousands of such stores across the country would be a brilliant business plan. The same applies to the individual model stores, comic book stores, aquarium stores, etc. across the country. I suspect few make a lot of money--and it probably still gets harder rather than easier--but they can work on an individual basis.