I read that stores are putting the Christmas stuff out in the hope of generating sales as retail is suffering at the moment. Not sure it helps really, as personally I feel like it devalues everything. Instead of the delight of seeing new decorations in November and getting excited, it becomes the "same old same old" display I walk past for 4 months, so I'm less inclined to buy as it's currently too early, and then just old and boring.
Did you know you can get tree decorating services to decorate your tree. That seems sad to me as every decoration we have was bought for a special memory and I love reminiscing as I out them on / take them off every year.