What assumptions are you relying on when you assert that more work on the site = more revenue?
Sometimes it's because I find a way to get more traffic, and sometimes it's because I can find an ultra-targeted advertiser to pay for an extended period of time. The problem is that I have zero interest in the subject material and would prefer to rid myself of it completely. But it's definitely got significant value and I want to make sure I don't just give it away for nothing.