Interesting question and I liked afeura's response.
I'm wondering why someone with an MBA is more valuable to an employer,
I feel I was more valueable to my employer as I had a broader range of skills than other managers who were promoted directly because they were technically excellent. Being a manager requires a different skill set to being a good technician. I was better equiped to instigate professional performance management systems, with out engaging the ire of the unions. I say identified less with my speciality and more with the organisation as a whole and I particularly identified with clients as the most important stakeholders.(unusual in my industry where staff are usual seen as the most important)
I was well equiped to manage budgets effectively and creatively.
(not that that was rewarded!)
I understood better how to grow staff within the organisation and how to network effectively with other organisations, universities etc to offer a better service to our clients.
or more likely to be successful if they start their own business.
I think the US is better at offering MBA programmes that appeal to the entrepreneurial personality. One of my classmates launched her own film business and one friend who did an MBA in the US...he launched an international software company, which seems to be successful. But in general my classmates and myself were cogs in the corporate machine.
Doing an MBA doesn't increase you IQ. It doesn't change your personality
Neither does learning to read and write, but it offers you useful tools to deal with the problems you encounter.
Some say it gives you contacts, surely that's not a good enough reason to do one.
Not as a stand alone reason, but it is an important part of doing the MBA.
So if I needed advice or direction on a marketing or IT issue, I would have people I know well who are specialists in these areas, to ask for direction.
Most people who start a business obviously dont have an MBA, would they they better off if they did ?
Most business start-ups fail.
Would an MBA reduce the failure rate?
Probably because fewer people would have started half cocked.
Should all entrepreneurs be forced to do MBAs? No, they are too expensive, but there are reasonable mentoring systems in place for budding entrepreneurs who seek them out.