I agree to some degree. I think ambition is absolutely necessary, but I think passion is something that can be developed over time. I've had some false starts in trying to learn how to program and each time I did have some thoughts that maybe I'm not "passionate" about programming. But I found that my passion, appreciate, love, etc for programming grew when I stuck with it, got better and realized what all I could do with it. Maybe this was the case for me because programming just didn't click for me in the beginning. I'd argue that we don't just have predisposed passions, but rather passions develop as we go beyond the surface level of our interests.