Its my best guess lots of people never get a chance to work on something that they have a genuine passion for. A genuine passion is something you'd do even if you didn't get paid for it; you know you've got a passion for something when you realize your loving hobby is also your job.
Perhaps its not by choice we can't do what we're passionate about. Practical considerations abound: if we can't pay the bills, then we don't eat, then our families don't eat, and we'll end up living by the roads.
But consider this: if this world was governed by what was practical and what was not, we would still be living in darkness without Edison's persistence, we would still be shackled to the earth without the Wright brothers' courage, and Malaysia would still be a rubber plantation. Take the risk worth taking because you'll never know where it leads you.