I find Elon Musk exceptional, even amongst successful business people, due to his seeming goal.
The meaning of life is generally very subjective. Leading a good life, leading a successful life, leading a productive life, leading a happy life. These all rely on personal and societal definitions of good, success, productivity, happiness. The activities associated with these words change with time.
There is another, more concrete option. The meaning of life is perpetuating and increasing life. This is generally narrowed to perpetuating the life and growing the population of your species.
This second definition is much less judgmental and much more inclusive. It is not about determining what anyone should be doing. It is about figuring out how you can help ensure as many of their futures as possible.
This is what I find exceptional about Musk. Based on the two business ventures he is leading it seems he may ascribe to this rarer second definition.
Tesla is at the forefront of electric cars, which help reduce fossil fuel consumption, self driving cars, which have the potential to significantly reduce motor vehicle deaths, and creating better energy storage, which is a key to broader adoption of renewable energy sources.
SpaceX is about enabling humanity to expand beyond this planet, which is necessary for the population to continue to expand and potentially necessary for humanity to survive. This venture is especially interesting because it is a very publicized and long term investment. Most investments look for returns relatively quickly, especially in the age of information, but SpaceX might not be successful, much less necessary quite some time.