Or to put this differently. If I was working for some larger company as a developer, and I went to management and said "I have decided that I want to quit development and work in marketing", they would turn me down. And rightly so, because A) it would be bad for the company to lose my development skills, and B) there is no reason to hire me as a marketing person when there's many more out there far more qualified and experienced in marketing.
So...if this would be quite clearly the correct course of action if I worked for someone else, why would I not follow the same thought process for my own company?
I am not saying MBA skills are not valuable. But what is more important is ability to write pithy blogs, write tons of emails to your potential customers, investors and do lot of other routine activities to keep your startup afloat. None of this requires MBA as such in the initial days.
Your passion, reading some of the best blogs out there on specific topics is more than enough provided you take all the advice as just that 'advice' and tweak it to apply as per your situation & needs.
Exactly my feelings.