Space elevators are like nuclear fusion: a lovely idea that is always 20 years ahead of today. There are countless real-world practical engineering problems that academics love to ignore yet which in real life will almost certainly render the comic-book concept infeasible. Resonance effects caused by the awkward fact Earth has an atmosphere, for example, are sufficient alone to dampen enthusiasm for such dreams. There are dozens more objections that have nothing to do with carbon nanotube-derived supermaterials but everything to do with practical engineering.

As for a tube running from Earth to a moon orbiting a planet millions of kilometers away…. have you looked at the relative orbital paths of any two solar system bodies, never mind moons orbiting such bodies? You’re talking about a tether that must accommodate massive changes in length, massive stresses causes by resonance, and which also can magically compensate for the orbit of a distant moon around its own planet. The math alone is intractable; the engineering consequently entirely infeasible.

Finally there’s always the cost-benefit analysis. If it is simpler, cheaper, and lower-risk to accomplish a task by utilizing already proven technology, why incur massive complexity, cost, and risk on totally unproven and highly infeasible concepts that offer no real return on investment but massive opportunity for costly failure? China may wish, for political reasons, to play the JFK card but that’s a very different proposition from actually producing anything tangible decades from now when both the political and economic situations will have altered and no one will remember such grandiose promises.

There are many dreams; there are far fewer practical realities.