Owen Gleiberman Chief Film CriticThe blockbuster age, it’s usually said, began with the release of “Jaws” and “Star Wars.” But you could argue that the blockbuster mentality didn’t fully kick in until ordinary moviegoers began to fixate on the question of what was doing well (or not) at the box office. It’s hard to hang that development on any particular date or movie, but it probably coincided with the rise of “Entertainment Tonight” (which premiered on Sept.