I used to think that the space elevator is a great and necessary concept for building a space-based civilization. How else can we get enough raw physical material into space? There's no way rockets can scale up to the enormous tonnages that will be required.
Now I think the solution is to build an industrial base on the moon. The lunar factories and mines (mostly run by robots) will harvest the necessary material, do some initial refining, and then fling the products into space using mechanical techniques (something like SpinLaunch, or a giant catapult). Lifting off from the moon is far easier than getting off the Earth (think of that tiny lander that the Apollo astronauts used).
Now I think the solution is to build an industrial base on the moon. The lunar factories and mines (mostly run by robots) will harvest the necessary material, do some initial refining, and then fling the products into space using mechanical techniques (something like SpinLaunch, or a giant catapult). Lifting off from the moon is far easier than getting off the Earth (think of that tiny lander that the Apollo astronauts used).