If we see interest rates at 2% again(or whatever) things are going to be tough enough you aren't going to want to access it, is my guess, or you may have to access it, and in that case, a land purchase is probably going to be the furthest thing from your mind. The bond market is basically calling the feds bluff right now, so long term interest rates aren't really dropping, as has been noted. 

This is all the disjointed "thinking" I can come up with before my first cup of coffee is done.