The original poster has only MD80s, and, right now, there are none on the UM. I can't find any 737-500 either for my own use. I don't even speak of E145, my other fleet group, a brand new fleet in 1996.
And??? That's the game. There are a lot of players, and you've got to make decisions : go for another fleet group, buy new planes, or wait a little bit. Adapt. Especially when things don't go as well as planned. If the plan is to lease every MD80 on the market & expand as quick as possible, then the plan has to be adjusted. Not the GW. There are 862 aircraft available right now on the used market, plus plenty of similar aircraft to be bought(TU204, anyone?).