We've "succeeded" at space flight about as much as we've "succeeded" at AI. Yay, man on the moon! Over half a century later, and it turns out that the "next small step" - man on Mars - isn't so small and still hasn't been achieved. Anything remotely resembling sci-fi-style ubiquitous space travel remains exactly that - sci-fi!

Flying a plane and intercontinental flight are different levels of the same remarkable achievement.

A man on the moon, or the SpaceX rockets that land and can rapidly relaunch, both feel like hard problems that have been solved, although it’s not the next hard step of intergalactic space travel.