Telling people that passion is the key to success does those folks a great disservice. Somewhere down the road, they will discover that no one cares about or shares their passion. The will find out that while they are passionate, they haven't done the work to be really good, and they know nothing about selling, marketing, leadership, management, finance, their competition, serving customers, or all the other facets of a successful life or business. They are passionate, but they are passionately incompetent. They don't have the skills to excel. All they have is their passion.
Try cashing that at the bank.