The 'nail' in the Space Elevator coffin might not have actually ANYTHING
to do with the technical feasibility of building one, but that the
environment that it would operate within has become too hostile!

Scott Kozel posted about the hazards of aircraft hitting the cable, but
a far more likely scenario will be a member of a LEO satellite
constellation, such as Starlink or one of it many competitors that may
be launched.

Having an entire constellation of thousands of low Earth orbiting
satellites may very well present too much of a challenge to have one
stable ribbon cable extending vertically across the orbital planes of
these constellations at the Earth's Equator. The orbital pathways of
Starlink look far more like a weave than a circle. Requiring frequent
and potentially costly moves of an Earth-side anchor even if it were
designed to be mobile from the get go. A further design complication.
This may render the entire concept moot. Like setting up a lemonade
stand in the middle of an eight lane superhighway!

So if this ever happens, maybe Moon or Mars will be the first, even if
technically doable on Earth!

Dave