OP, I completely hear you on this. Last year, I went to At Home the first week of October to look for some fun Halloween yard signs. I managed to find three pitiful, leftover skeleton yard stakes (I picked the least-scratched one) and mere scraps for fall. I couldn't believe it. But Christmas was in full swing. I actually picked up a Christmas door hanging while I was there to not be in the same boat in November.
This year, I went at the end of August and picked up a pretty glass pumpkin and a fall doormat. When I went in mid September, half the fall stuff had sold through and almost all of the doormats were gone.
I know not everyone shops at Hobby Lobby, but they had a TON of stuff just a couple of weeks ago.
And I can't speak for Walmart, but Target really has been phoning it in for Halloween/fall for three or four years now. It's the same stuff every year and not near the options they used to have. Personally, I think At Home has really stepped up their collections and does a better job.
DS: Raising heck since 12/09