I just finished a book where the hero is considered insane for investing his wealth in interstellar travel. And it is true that such a venture will almost certainly not be profitable, at least in the lifetime of the investors.
But odds are that human beings will not survive the next million years unless we get beyond the solar system, already too many close calls with war and disease. So how do we get there? Why do we get there? I have faith that we will though.
I’ll be a million years old that time, plenty of time to figure out all of the ways to make money. Ask me then.
Here is an article that asks the same question.