Isn't the purpose of a space elevator, not having to deal with gravity? but this is at least ten thousand years in the future, surely human beings will have solved the mysteries of gravity by then. how else would they colonise the whole galaxy... and we see in the show that they have solved the gravity. smallest ships can ascend from the surface and go into deep space without having any difficulty, they have hovercrafts in the show. gravity is not an issue in this series.. so why is there an unnecessary space elevator? just for show?
(sorry for butchering the grammar, but I hope I could make myself clear :))
The elevator was a plot device, nothing more.
Here's the problem with the space elevator in reality ... it's a retro-20th century notion, popularized by Arthur C Clarke some ~70 years ago.
IMHO, it's already archaic from the perspective of Sci-Fi.
When ppl are capable of commandeering a shuttle craft into orbit, within minutes of ground departure, why would they want to queue up for a 12-14 hour vertical train ride (no sleeper carriage), the same amount of annoying time it takes to go from NYC to Tokyo with today's subsonic jet airliner? And this doesn't even take into account the additional travel time it takes to get from let's say planet A in the Alpha Centuri system, to planet J in the Sirius system on a star cruiser.
Star Trek already closed this issue by ppl taking a small shuttle into space and then, taking off on a long distance star cruiser to hop around from star system to star system.
Trantor, being the megapolis that it is, will have no trouble having shuttle mini-spaceports at every urban nexus, with rides into high orbit to dock onto jacked up space stations to board interstellar vessels. In a way, it'll be a lot like today's major airports but in space instead of on the ground where yes, security can isolate potential terrorists, coming and going from the planet.
One or two lone bombers, with nano-explosives, wouldn't be able to cripple the entire planet's space travel if it wasn't for that single point of failure.