I think everyone should put in what they can. The bigger guys have more to spare, not typically less. I just have this image of Jabba the Hut screaming See fah luto twentee, ee yaba...

But I'm strange. Anyways my point is that half the time I'm asking people in my alliance "anybody need something, I have a ton to spare" because between farming, fighting, and conquering in the end it's not the bigger players that need the help. At least from my experience...