Surely there is a half way house though? Why not have a couple of later nights?
I get the point that younger kids may be crochetty if they are up after hours but parents know what their kids are like and should be removing them before this (or know what the consequences are likely to be)
Saying that they are closing earlier as it suits younger kids is a complete cop-out - no one is forcing anyone to stay until the end.
If they just are a bit more honest "look the figures just dont add up" then you don't have any more discussion about it and everyone knows where they stand.
----After thought----
We are all used to DMR being a theme park. We all go because its a theme park and that means rides and attractions. I think we have to change our mindset. This isn't a theme park event, rather its an event at a theme park. The point is to sell grotto and train rides and hot chocolate, rides and stuff are just something to differentiate this Santa offering from others and justify the entrance fee.