Ask HN: Is attitude more important than knowledge?

I am old and overeducated. I grew up poor with uneducated parents, after high school I had to get a job. Later in life I put myself through college all the way to an MBA from a top school. All my life I have wanted to be an entrepreneur but while I started a few companies, they all failed. Over the years I have heard here and there various versions of "Attitude is more important than knowledge" and each time I was furious, since I have invested a lot of time and money into acquiring knowledge. Alas I am starting to suspect that I was wrong all along. While "some" knowledge is essential in business, "attitude" triumph knowledge when it comes to entrepreneurship, and business in general, by orders of magnitude. So, what does HN think? And how can I leverage my wealth of knowledge to become a successful entrepreneur?