Most likey we've done all the low hanging fruit: supersonic flight is categorically more difficult than subsonic yet is a diminishing return given that so much

Most likey we've done all the low hanging fruit: supersonic flight is categorically more difficult than subsonic yet is a diminishing return given that so much time is just spent preparing for the flight. And, Peter's opinion not withstanding, it is impossible to communicate faster than light which is where we are. But if we have become decadent, it hardly surprising in a society where opinion is give more weight than facts and people are not even willing to preserve their democracy.