There's not been that much progress in the 20 years since Brad Edwards proposed the first actually feasible space elevator design. It's difficult to say whether

There's not been that much progress in the 20 years since Brad Edwards proposed the first actually feasible space elevator design. It's difficult to say whether ultra-strong CNT cables are something that's perpetually 20 years away, or something that follows the "progress is slow until it suddenly isn't slow" exponential curve.