Every year the Christmas feels to be starting earlier and earlier. It's not even past mid October and the Christmas products have been in stores already for weeks.
It's not like there wouldn't be any other celebrations for stores ro sell seasonal stuff around this rime od the year. Even Halloween, which is much closer hasn't gotten much shelf space at the stores yet. And it never will because the prime aisles are filled with Christmas chocolates, Christmas, drinks, Christmas decorations and other Christmas products.
When, and why did it become such a big deal? Dedicating one quarter of a year for single holiday feels a bit excessive. Especially as most of it feels quite annoying. It's also a lot of single use crap that will be thrown away before the year even ends.
This extended period of everything being of the occasion does also make it feel not so special. You get used to it after the first few weeks, then get annoyed and by the time it's actually near it has become so common that it doesn't make any difference. At least it's gone fast after the Christmas is over and the leftovers are sold out with huge discounts.