As Mark pointed out, a lot of people refused the call before it even began and still more returned home, back to their comfort zone after encountering their dragons.
When presented an opportunity to grow, people sometimes feel unprepared or not good enough and shy back out of fear of the unknown.
Really your whole life is a Hero’s Journey, but some choose to stay in the first stage, hence “refusing the call.”
Others of us have several Hero’s Journeys. We may even reinvent ourselves each time we go through a cycle.