Made possible by modern heating.
Let me explain: My favorite flavors, those chocolatey, vanilla-y, caramel-y ones, heavy heavy flavors. Make you very very thirsty. Even sorbets make me thirsty. This is not what you want in the heat of the summer.
But in the winter, that is when you crave something rich. Sometimes/Oftentimes you want hot chocolate, but somethings you want the thick creamy slightly hardier texture of ice cream. The cooling nature is simply a byproduct, a necessary side effect for textural purposes. I mean, how often have you even had hot chocolate pudding, or hot chocolate mousse? They simply do not exist in hot temperatures on account of chemistry!