There are various reasons for why SpaceX is so popular, but I think most important is because of Elon starting from scratch against incredible odds of failing,

There are various reasons for why SpaceX is so popular, but I think most important is because of Elon starting from scratch against incredible odds of failing, combined with massive resistance from established companies and initially even the government (to the point of Elon crying during an interview), combined with Elon's novel and bold designs/goals and SpaceX's engineering feats. Add to that also their willingness to be open and share success and failure with the world, and I think it becomes easy to understand why they have so many passionate fans.