Furthermore, as technology and quality of life increases, risk tolerance decreases. I think this trend will continue. Historically, technology has increased fast and uniformly enough that we've still been able to do great things. But if health care technology improves much faster than space technology, then we may never leave orbit again.

(This trend holds at least at the societal level, and over long terms. For individuals over the short term, it can be weaker, e.g., you might buy a helmet or a safer car, and then ski or drive more dangerously.)