fallacies of distributed computing prove themselves time and again.
Take the (mystical) "cloud", for example. Most enterprises are going to build their own, or partner with on of the big players to implement a 'private cloud'. Cha-ching! What's more, the cost and time required to migrate an enterprise level application, let alone the complexity involved changing existing business processes and policies to live on new infrastructure at the scale they require is often mind-boggling.
Don't get me wrong, my life with virtual hardware has gotten far easier and I wouldn't go back in a second. I do, however, appreciate the cost and complexity it takes to get there.