This to me is a rediculous assumption - the overheads would be astronimical for something that had never happened. I'm sure Sony had a level of 'expertise' but the breach was potentially very bad so brought in unbiased experts to give a full account of the damage so they know the worst case (ie staff won't be able to cover up or only tell half the story). Certainly I can't think of any company that doesn't use a form of 3rd party support...even Microsoft.
No company has 100% cover for every scenario - especially in the current climate where companies are cutting what's seen as 'fat' - even where I work bizzare descisions seem to be made and good knowledge seems to be made redundant - alternatively maybe they just didn't replace a person who had recently left, who knows - but the point is the same, no company has every angle covered no matter how important it is - every company/person improves aspects after bad things happen, unfortunately this was a very bad thing.
Look at airport security - it's fair to say that there's more than enough evidence to prove my comments are valid - and in those cases we are talking peoples lives not data!
And that's all I want. For Sony and all other companies in this situation to recognize that:
This was a disaster.
Sony's response to the disaster was unacceptable.
They all need to take the steps necessary to improve their own security and their ability to respond when the next attack occurs.
As long as this happens I'll be satisfied and at least some good will come of it. OTOH, if the collective thinking is that Sony did nothing wrong and this is the level of response we should expect than this is exactly the level of response we will get going forward from the industry as a whole.