The graying of audiences for what might be called higher culture (let’s be objective and call it more expensive culture) has become a perennial topic of concern. It is accepted wisdom that young folks don’t go to theater much (I’m not talking about tweens going to “Wicked” on their parents’ dime), and one presumed reason for their reluctance is the price of entry. Still, hard evidence pointing to price as a serious barrier — as opposed to, say, a resounding lack of interest — has been hard to come by, because pricing trends go only in one direction.