Yep, today's Dilbert was uncomfortably close to reality...especially the vague objectives part.
The growing omnipresence of middle managers is a reflection of a couple of things, I think. First, whether public or private sector, large organizations are transmuting by leaps and bounds, and the very idea of a single middle manager who can keep track of what is going on in multiple work units whose work is under constant transformation seems preposterous. Add to that the naive belief in the notion of the generic manager, and it quickly seems unreasonable to force one person to learn all about so many different things. In other words, if you don't have anyone managing who has actually watched those business lines evolve over time, and understands them, then it is best to just stick one manager in charge of each specific business line.
The growth of middle management is also a reflection of what I like to call the cult of accountabalism we see around us these days. One component of accountabilism is what many folks like to call reporting burden. So, in order to make sure all that tax money is being spent wisely, there is an insistence on having someone in middle-management churning out the reports on how the money is being spent, as well as overseeing all those people working on all those reports. Greater emphasis on accountability inevitably leads to a thicker middle layer, IMO.
A cynical side of me might also suggest that the growth of middle management is a way to diffuse responsibility. That is, all those folks in the middle shield all those folks at the top from being held accountable (another component of the cult of accountabilism) for decisions they were too underinformed and overcommitted to make or be aware of.
Finally, when cuts have to be made, it is the middle managers who are left, and the underlings who are cut. Like hair getting caught in the bathroom sink drain, they start to add up. Maybe it's because their severance packages are too costly to let them go. Maybe it's because they're all friends from meetings and can't face cutting each other. Who knows. Whatever the case, it can often happen that when middle manage X is somehow out of employees, someone higher up will find a spot for them somewhere else within the organization, and a work unit that used to have one manager, is now split into two and has two managers.
I guess the $64,000 question is how one identifies when an "appropriate" mass of middle management has been reached within an organization that allows for effective oversight yet still permits good connections between the very top and the very bottom. I don't know that anyone has a particularly good answer for that.