I don't know, but I'd guess it's a combination of two things:
* It's tricky to message right. Most theaters do some dynamic pricing, with discounts for certain hours or certain days, but stronger or more complicated schemes inevitably start to come across as "we're taking more money out of your wallet just because we know you'll let us".
* Charging too high of a price can shift your market segment. Most movie theaters sell themselves as entertainment for the average Joe, and having special events with $50 tickets really undercuts that.
* It's tricky to message right. Most theaters do some dynamic pricing, with discounts for certain hours or certain days, but stronger or more complicated schemes inevitably start to come across as "we're taking more money out of your wallet just because we know you'll let us".
* Charging too high of a price can shift your market segment. Most movie theaters sell themselves as entertainment for the average Joe, and having special events with $50 tickets really undercuts that.