Even though this statistic shouldn't be surprising I still find it completely fascinating. I am certainly guilty of this myself, although I have never started a podcast there are more unfinished projects that I was sure were my life’s mission sitting in a drawer somewhere than I can count on both hands.
I think you’re absolutely right- committing to mastery is key. Another component I would add that seems intuitive but should be formalized is that whatever a person chooses has to be a real passion of theirs. It seems as if this is the only thing that keeps the spark alive in the dead of night.