Watching old movies is like spending an evening with those people next door. They bore us, and we wouldn't go out of our way to see them; we drop in on them because they're so close. If it took some effort to see old movies, we might try to find out which were the good ones, and if people saw only the good ones maybe they would still respect old movies. As it is, people sit and watch movies that audiences walked out on thirty years ago. Like Lot's wife, we are tempted to take another look, attracted not by evil but by something that seems much more shameful -- our own innocence.
In the arts, the critic is the only independent source of information. The rest is advertising.