Bookstores are no longer viable, because Amazon has obviated the need for a brick and mortars store, and it passes the benefit on to both consumer and author alike, in reduced prices and thus increased sales.
Since Amazon is not in the authorship business itself, since it gets an equal profit on all books, its book business is a lovely example of markets working to further society.
Amazon's problem is in the use of data metrics on its giant store to create products that compete with its partners. The Amazon Essentials line is anticompetitive IMO, because as the operator of such a large platform, Amazon has a responsibility to the US economy.