This is a very personal opinion,
and I can't really support it with data, other than rather a lot of 'stories', but, the biggest stumbiling block, in my opinion, is management.
In my (not very humble) opinion the major problem with virtually anything that goes wrong is management - specifically giving the decision making process, and final say, to people who simply do not understand the task, or how the proposed solution(s), work.
There's actually a sort of tenet still in place that says management skills are management skills, and it's almost harmful to know too much about what you are managing - that (perhaps) holds good provided the management stay out of the nuts and bolts decisions, and restrict themselves to overall strategy... in the UK we seem to be devoted to ensuring management delve into the tactical level.
MPs, in my view, are the ultimate evolution of 'know **** all, have limitelss power' management. With all due respect to John Prescott (as one recent example) how the **** do you get to be (ostensibly) the second most important decision taker in the country based firmly on a career as a ship's steward?
(Or take Tony Blair - number one, apparently based on a solid career as a ... dunno, sponge?)
Still, as long as there's a decent bottle of port at the end, who cares?
Dave