Which factor does Beatty claim is responsible for the creation of the fireman profession?

Beatty notes that the firemen's real job started during the Civil War, corresponding with the advent of photography. Film, radio, and television later sealed the deal.... tabloid magazines, abridged novels.... all replaced the classics. Real literature wasn't needed, the populace was willingly dumbed down, and the government liked it that way. Intellectuals aren't desirable.... they can think, and then they question.