I wouldn't go as far as "very little to show for it."
NASA has done some amazing stuff.
But most of the projects have been one-off spectacles, like leaving flags on the Moon and nobody going back.
People will go into space in a big way when they can make money at it. That's been the history of most Earth colonization, too.
The nice part is that when we colonize the solar system we won't be kicking anyone out who already lives there.