Comment by threethirtytwo

I don't want to introduce 50 tangential branches to argue about with no end in sight.

It's not pessimism, it's reality. Think about how unlikely it is. Humanity had one stretch where we reached for the stars and that stretch ended and by sheer luck some crazy guy made it cheap. What happens when he's gone? Will it happen again? Most likely: no. In your lifetime? Even Less likely.