I think the problem with such a mission right now is the high probability we could launch a faster mission in the very near future - i.e. with NASA looking at spaceborne nuclear propulsion again, we could send much more capable telescopes out faster - which is not just an "I want it now" benefit: time in space is time you run potentially having components wear out or break. So getting them onto their missions ASAP is a huge de-risking element.
I wonder - and I am sure this has been examined to death - if there's some calculation that can be performed to find the "optimum" wait-or-release-now pattern, given a certain rate of technological development vs. distance/years ...
I am sure there are calculations for this ...
PS. Of course, the rate of technological development is the unknown variable hete, I am sure.-
I imagine such calculations immediately break down when you make the input (funding, interest) depend on the output. Which is the case in reality.
For example, say your calculations say that the optimal time for the mission is 10 years from now, once a currently in-development propulsion technology matures. You publish that, and the investors, government and the public, all motivated to support you by the dream of your ambitious mission, suddenly lose interest. Your funding dries out, as you're repeatedly told to call back in 10 years. The fact that the 10 year estimate, having been dependent on existing funding, is now "literally never", escapes them.
See also: "nuclear fusion is always 30 years away". It is, because original 30 year timeframe assumed continued funding that never happened, and it's not happening because "it's always been 30 years away".
I recall a US commander in Afghanistan saying more or less explicitly that they were doing that - his rationale was that whatever military objectives they were given would be unachievable if Congress pulled them out, therefore the highest priority was always implicitly the preservation of goodwill via e.g. avoiding excessive casualties. Feels back-to-front to me, but maybe it worked for him.
Dunno about Mark Twain, but it appears the best time to launch men to the Moon was more than half a century ago. The second best is now...ok, a year from now...I mean a few years from now.
