My house DID last for one year, thought royal icing decorations fell off here and there. Royal icing items again fell off the following year. This time I threw it away. I think, if one could spray with shellac, thickly, this may hold it. But it won't look the same.
Kids can make 'em on used from-school milk cartons.
You can freeze whatever cookies that haven't become too hard. Just wrap and seal well. Place in a plastic bag and then into a box. For cookies that HAVE hardened, these can be crushed up and used as 'sand' on outdoor scenery decorated cakes. Don't use cookies that contain nuts or other ingredients unless you are sure the people eating them aren't allergic.