wasting, er, researching online for hours, the best I was able to come up with was that Charles M Shultz decided that since Christmas and Easter both had mascots, Halloween needed one too. Click here for article.
After all, it is a major holiday and most American holidays involve treats and presents.
Thus, the Great Pumpkin was born.
Of course, given the gourd carnage on the streets the day after Halloween, I understand why the Great Pumpkin never shows up.
But I still don’t know why Charlie Brown received rocks and I do love his costume.