I've never seen a case where outsourcing of general-purpose IT things saves money over the long-term. It might make the budget look better for a year or two. Which, I think, is the motivation for a lot of the people making decisions to outsource. It is cheaper right now, so who cares about later?

Special-purpose stuff can still be cheaper to outsource, though. If I need something to work next week and it would take my staff a month to get up to speed, I'd spend the money on outsourcing it.