The secondary market on wine is very economy dependent, meaning that it really depends on how much disposable income is available. Right now, it's not that good, and you only have to look at Bordeaux futures pricing to figure that out. And just like supply and demand, the stuff that is hard to get is going to be priced higher. There is also the inherent risk that the wine you are purchasing wasn't stored properly, and you end up buying real expensive vinegar.
I don't do it, but I know of people that have sold wine out of their cellars. What usually ends up happening is that they take a pretty hefty discount to get a bulk sale done.