"What do you tell an affiliate who says he's going to quit because nothing is coming of his efforts and hard work?"
You should to say to affiliate, as I said to myself, that he didn't find the right way, the right tools and places on internet to sell and make new active members. It is easy but wrong to quit, he must to search, ask and learn more to find the way to results. "Know how" looks simple but it reality it is the hardest part.