Obviously this is meant metaphorically. On a much more concrete level equivalent questions might be, "What's the point of developing hypergolic depots when they're just going to be made obsolete by cryogenic depots?" Or, "What's the point of developing rocket launch technology when we could just wait for space elevators?" And so on.
because future obsolescence is not a good measure of the value of a technology.
I think I have often met this "Waiting for Zefram Cochrane" attitude and it is quite a worry. I sometimes suspect it actually is a legacy of Star-trek.
Does the sort of hypergolic engine that could benefit from a propellant depot exist yet?
Usually, it's better to go now with what you have rather than wait for something better.
In a military analogy, you fight with the army you got not the army you wish you had.
...they subconsciously think technology advances on its own.
Sometimes it seems to me that people advocate "waiting" for future technology because they subconsciously think technology advances on its own.
Sometimes it seems to me that people advocate "waiting" for future technology because they subconsciously think technology advances on its own.If we don't develop technology, it doesn't get developed. It's not a question of whether or not X technology will be obsolete once Y arrives, and whether it's worth it to develop X in the meantime. If we just "wait", we will get neither X nor Y.