Is it possible that one reason people leave at the interval is because they don't want to be out too late?
More than possible, I think, Tony! A few UK metropolises (London, Manchester, Birmingham, Edinburgh) "rule the roost" and are providers of culture for a huge area around. Very often public transport won't deliver. For example, I have a friend who lives in Leyland, effectively a suburb of Preston. If she wants to get to opera, it's usually a case of going to Manchester... but getting back means bailing-out before 10pm.
I'm sure there is a major untapped market in more local provision of the arts!
