When I write longhand, I can pretty much keep going as long as I'm not interrupted, because my brain goes just a little bit faster than I can physically write the words down. Apparently that makes me wordy.
I wrote a story out longhand two weeks ago, and I wondered why it was taking me so freaking long to type it up--I would type a bit of it and lose interest, and come back and type some more the next day, and so on. Finally I typed the last of it tonight. Even after cutting one minor character and a few lines here and there, and several paragraphs near the end, it came to 5,200 words. 5,200 words in a story where nothing much happens!
I swear, I never used to have this problem. I used to underwrite, and later I'd have to go in and add stuff, mostly description. Now I'm working hard at putting the description in the first draft, which is good for me as a writer but not so good for my wordcount.
I think there's no market for this story, either. It's sort of YA, sort of funny, has too blatant of a moral, and the core idea has probably been done to death. And, of course, it's way too long.