You have a good point (and it's not the only time the ST writers used a sentient being that had evolved in interstellar space).

What I think RL has in mind, though, already assumes a certain biological commonality with humans: having evolved on the surface of a planet, being required thereby to invest large portions of resources to achieve spaceflight.

There've been quite few threads over the couple of years the Zone's been around (not counting previous incarnations) about necessary and sufficient human motive for expansion into space. Is "the far side of the mountain" enough? I think so, but not everyone does. Is that what's gotten us as far off the planet as we have so far? Will it be what keeps us out there, and going farther - or will it be as Bowser suggested, to exploit what comes into our extended reach, probably because we're running out at home?

How much - if any - of this might have analogs in other planetary systems with four or five billion years of separate evolution, including the planetary makeup of the system itself? (Again, I think of the Moties...) And why, or why not?