Jeff, for the record, I am no longer an Exchange admin - but have done it since the olden days. Secondly, sorry you cried over my post. The concept of having a poorly behaving product is one thing, but to justify it's behaviour was a little over the top for me.
To assume that Exchange is the only thing on that box is crazy. There could be other connectors - or what about backup software and a local tape drive. Imagine the backup taking 10 hours because it can't get enough RAM to do it more efficiently?
At least something like SQL Server let's you have some control over how much RAM you want to give it.. but this main post was a little out of control in my book.. Sorry I offended.