I could say 'every instance I've ever seen' and you could counter with 'every report written by someone to justify the outsourcing decision'.
If you would like to believe that IT is a replaceable commodity, and that outsourcers are the only safe future, I'll not argue.
I believe - that while you may be right - that IS the way business is going (at least for now) - that this is a foolish, short-sighted fad that is bad for most businesses that indulge in it. Larger places full of stagnant management cultures may derive benefit from outsourcing - that doesn't mean it's a good or effective way to go. They see dollars (or pounds) on a spreadsheet and act like that's the cost; they see numbers of employees and figure that = 'effectiveness'.
I've heard not one argument to dissuade me - even a little - from my opinion on this matter. I've seen too much. Call me jaded.