Just replace the word "Entrepreneurship" with "Sales" (which is similar) and perhaps you can understand.
Not all of them can possibly fail for completely unique reasons.
Almost every job has quite a bit "on the job" learning that you won't get in your academic studies. An MBA still teaches a lot of the skills, whether they be in finance, business planning, networking, IP issues, or presenting, that are useful for entrepreneurs. I imagine an MBA focused specifically on entrepreneurship would have even more useful stuff in the curriculum. Would be great if someone with such a qualification could chime in. A friend of mine with an MBA had one course where the main project was to basically to development a business from scratch and pitch it to real investors. Several students went on to launch those businesses after school.
A typical MBA involves the study of topics such as marketing, finance, risk management, accounting, economics, statistics, operations, HR, organizational dynamics, business law, and strategy.
Many of these can easily be adapted to be more useful for entrepreneurs. A finance class can focus on venture capital more than the bond market. A marketing class can focus on new product development more than the promotion of existing products. A law class can deal with the issues most relevant to startups. The accounting needs of a startup exec are different than those a future partner at Deloitte. etc.
As a clear example of the type of content that an entrepreneurial class could cover, Steve Blank's book Four Steps to the Epiphany originated not as a book, but as the notes for his class at Haas.