The answers are still forming:
I would argue that there is no "average" newspaper reader. There are particular readers, each one with a set of interests that somehow intersects with what the newspaper writes about. And I would observe that reviews affect theater companies directly. A series of excellent reviews in The Oregonian, for example, helped Third Rail Repertory Theatre leap into the local major leagues in only a couple of years. Which means that somebody is reading them, and even acting on them.