You demonstrate a fundamental misunderstanding of human nature - we as a species are compelled to understand that which we currently do not. Thus, what exists outside of our planet is of greater mystery and intrigue than any vast sum of money. I, for one, would happily be involved in a space-faring program. I would rather help discover a planet, or something world-changing like "the Earth is spherical", than lie to the entire world and make some money.
Also, you fail to understand that there are organizations other than NASA that explore the outer boundaries of Earth. Virtually every country that contributes to the global market has some investment in a space program.