I disagree on pretty much all counts here.
I especially disagree with your proposition that people with MBAs are likely to be better at running businesses.
An engineer friend of mine went back for an MBA from a top school. He said the one non-obvious thing he learned in two years was the principle of comparative advantage. The rest was stuff he could figure out from first principles and a modest amount of thought. He said the real value to his career was the the networking with other young up-and-comers.
Moreover, not all knowledge is beneficial. A chunk of MBA training is in effect learning to be glib about business while sounding authoritative. That training might be beneficial to the degree-holder, but it can be harmful to others, including the company.
Or look at the extent to which a firm replete with Harvard MBAs totally destroyed a company while profiting handsomely: http://www.nytimes.com/2009/10/05/business/economy/05simmons...
I also don't think you can separate MBAs and professional management. The MBA is the infection vector for many of the worst ideas in management. It's also self-perpetuating: MBAs extract cash from companies and donate heavily to business schools, perpetuating both the ideas and the caste system.