Bookstores are not well known for fabulous profit margins in the first place. It doesn't take much to kill one, and the industry is just barely hanging on. Probably the store should re-cast itself as something other than a bookseller. But running a small business in San Francisco is a special kind of hell anyway, so why not provide a lesson for the ignorant as a final service?
Actually I wonder if the Borderlands owner is aware of what happened to the Kepler's bookstore in Menlo Park? Wealthy people in the local community crowd-fund it to keep it open. It's like a freaking church of the literary, except of course they're all communists. Considering how wealthy the neighborhood up-hill from the bookstore is, I bet Borderlands could do the same...
Independent bookstores fail for a number of reasons, I would imagine. Too many esoteric books and the usually unbelievable arrogance of the minimum wage workers. If I get any nonsense from an intellectual giant working in the Tarot Card section, I boycott the store.