There are a million variables in any given show or performance. Madeline Kahn seemed the perfect choice for the role. It seems as if she wasn't treated very well by the creative team or they didn't listen to her concerns. A couple of years later Prince had his leading lady only performing 6 times a week. Perhaps that would have helped Kahn. Look at another Prince show, Company, where the leading player was unhappy. They let Dean Jones out of his contract after a few weeks. If the lead is unhappy it doesn't make for a very happy experience for anyone.