I do not think that the rush for MBA is for the rush for money. Yes, it is ever present, but I believe someone who dreams of MBA is looking for a opportunities and freedom job wise. Having only a bachelor degree puts the limit to individual growth and thus doesnt lead to satisfaction. Also, people do not prefer Masters in their respective discipline because of the saturation and the lack of interest.
An MBA degree over hauls the personality of the individual, exudes confidence, guarantees satisfaction. His decision making prowess improves considerably without any expense of making a destabalising mistake both job wise and life wise.
Not to mention the prestige attached to MBA degree. Men become more suitable grooms, women becomes the target of many bachelors just because the scope it provides is limitless.
Also, consider being an entrepreneur. The only way to start a business is by accumulating initial capital. What fastest way to accumulate exp and capital than a MBA degree.