"The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision." -- Randall Munroe, xkcd, 2011-05-02 (mouseover text)
(no subject)
While that simple fact may fascinate a Hawking or a Sagan, it does nothing to inspire a G. W. Bush or a Trump or a W. Buffet. It tells them there's nothing out there to get - there's no opportunity for trade with colonies because any colonies can't get us anything other than what we already have. This is why Space travel is not in any way like early exploration/colonization of America, Africa, or the East, where they did have stuff (some natural, some technological) that we (Europeans) didn't have and so exploitation was worth it for those that invest.
But so long as we think that "out there" is pretty much the same as "down here" (and we now are pretty darn sure it is), there's just no reason to go out there.
Yes, that's the rational excuse, but unfortunately, as much as they are irrational with their ponzi schemes, the people with the money are making the rational decision here.
(no subject)
Tell them there's oil out there.