Yes, I think fandoms dry up. People change, and with that change can come a shift in interests and priorities. Bad experiences in the fandom are also s contributing factor.

I don't think I've "outgrown" HP yet. (Clarification: this is not to say that HP is childish or whatever - it refers to the changes I mentioned earlier.) I'm still enjoying writing, although I don't care about being in canon as much as I used to.

(If there are any typos in this post, please excuse them as the sun is shining on my monitor! @_@)