I don't see how the existence of one frontier of exploration precludes pursuing other frontiers of exploration. Has there ever been a period in which humanity chose to dedicate itself to one particular field of endeavor at the exclusion of others? If that's not what you're suggesting, what exactly is this comment supposed to mean?
I was responding to the idea that there are no more frontiers on earth left to explore. "frontier exploration is a massive part of many of our cultures, but the painful truth is that there aren't any left on Earth."
