The MBA is more of a credentialing and marketing expense than an experiential one. For example, some big accounting/finance firms only hire "top MBAs". No amount of garage-startup experience is going to get you in there; remember that not every educational/experiential endeavor can/should be viewed via the "Is this good for a startup?" lens. Don't underestimate the network effects of high-powered rich people who all went to the same school: many companies are unfortunately not meritocracies.