My answer wasn't wrong. But hey! You know everything. And I've only been playing since the beginning, so what do I know.
They put up the Thanksgiving screen, something done every Thanksgiving (when they get around to it). And at Christmas they might remember to put up the winter one. Then it will go back to the Halloween one. There is no neutral splash screen anymore. The one with the pumpkin king is the Halloween one.
I'll be more impressed when they change them more regularly and for different seasons and holidays.