I think there are as many successful companies started by careful market analysis as there are company's started by an entrepreneur's mission to solve a personal problem.

Jeff Bezos coldly examined markets and decided books were the right entry point into ecommerce. However, these don't make the best pr stories, and so aren't told...or in some cases, the story is just fabricated after the fact, such as Pierre Omidyar building ebay to sell pez dispensers.