No not at all!! An person who has his/her own venture might not requir mba..
a person having a family business or a grocery store or a restaurant are all entreprenuers.. they didnot need an mba for starting their business
mba can be done by anyone.. only thing is in business an mba can give a better perspective to things
MBA is a course which only helps polish the basics of management and business. A lot of people have succeeded despite being not too qualified educated. No doubt mba helps but then there is no hard and fast rule that it would help a business prosper