It's been building for maybe a decade? It's marketing that's been successful. Stores would set up earlier and earlier, and the people that really love Halloween would buy earlier and earlier, decorating earlier.

Then, at some point the term spooky season started being used outside of ads. I'm not sure what company started it, but places like party city were using it a while back for sure.

the war on christmas started with a preemptive strike by christmas invading thanksgiving, but thanksgiving had no allies. hardly even any songs. thanksgiving fell quickly. Now christmas has invaded halloween and even started attacking labor day. Halloween struck the September Alliance with Labor Day and has begun to fight back, but I keep seeing santas and elves dressed up trick or treating. THIS WILL NOT STAND. we shall defend our holiday, whatever the cost may be, we shall trick or treat on the porches, we shall trick or treat on the candy stands, we shall trick or treat in the corners and in the streets, we shall trick or treat in the hills; we shall never surrender, and even if, which I do not for a moment believe, this festival or a large part of it were subjugated and starving, then our holiday beyond the seas, armed and guarded by the halloween parade, would carry on the struggle, until, in gods' good time, the new treats, with all their power and might, step forth to the rescue and the liberation of the charlseton chew.