Sometimes outsourcing works, sometimes it doesn't. Highlighting a few examples in which it has failed does not lead to the conclusion that it never works.

So the author seeks to bridge the gap by identifying a fundamental flaw in the concept of outsourcing, in this case by noting the divergence of objectives between the two parties. Although true, this isn't the fundamental flaw the author is looking for. It simply identifies the importance, for outsourcers, of making their suppliers' objectives coincide with their own.

I wouldn't say the G4S case is one in which the government has failed in making objectives coincide. G4S will, in all probability, be found in breach of contract for failure to fulfil their obligations, and the government have already stated they will be seeking to recover costs from G4S, such that there will be no additional cost to the taxpayer for this debacle.