Don't get me wrong -- there definitely are jobs you can get cold based on having an MBA and no relevant experience, but most of the people I've met in that situation either don't have very enjoyable jobs or aren't making much money, or both.

I haven't tried to bust any kind of statistical analysis on it, but it seems like the MBAs that I know that saw real value out of the degree did either because of someone they met in the process of getting it (e.g., they work with a guy on a bunch of group projects, and then a year later that guy's company is trying to fill a position and he gets them in based on his strong recommendation from knowing the kind of work they do) or because it helped them push into management in a field they already were strong in (e.g. guy with a bunch of engineering experience moving into managing people doing the same kind of engineering.)

Your mileage may vary.