I feel kind of ambivalent about this idea. Let me show you the two sides I'm thinking about.
On the one hand I can see why a company would want to outsource its IT. These departments are big, complicated, expensive and difficult to set up. If these services can be better handled by an established provider it might save significant amounts of money and lead to more effective services.
On the other hand, IT departments are important and linked very closely to the operation of a company. If all these services are outsourced, it is possible that they will become distant and unresponsive. There is the risk that they will fail to meet the needs of both the company and the companies clients.