If you go to a top-5 MBA school, the opportunities are ridiculous. I know plenty of unimpressive people making $500,000 or more straight out of MBA school. But it needs to be a top school, and there are a lot of factors (e.g. work experience) that are socioeconomic rather than merit-based.
Top MBA schools are basically a 2-year networking event. I know a couple economics professors (at top MBA schools) who refuse to teach MBA students because they're sick of having the students demand of the Dean that they reschedule exams and classes to accommodate their leisure travel, and having the students win.
Most MBAs don't get the ridiculous, unearned compensation bump that merits two years off and an expensive degree, though. If you make $500k with no skills whatsoever, then you can probably pay it off. If your next gig comes in at $75k, that isn't bad by most peoples' standards, but it'll make it hard to pay off the student loans.