To be fair to them, I think trading down is a much harder task than it sounds.
I've never found it to be a huge problem. You just have to be aggressive in contacting other GMs, rather than them coming to you.
For instance, wdleehi has been trying to move up into the 1st from the 2.2. I don't know what he was offering, but something is better than nothing. I guarantee that Harrington would have been there at 2.2.