For in-system travel, we have to invest in space infrastructure, same as we did for the Oregon trail -> highways, the earliest sailing ships -> hydrofoil ships and aircraft carriers, and from covered wagons to cargo trains.

Skyhooks are a system of locomotion we could already do today, and save tons of expense on fuel and lift capacity, it’s just staggeringly expensive to do. We would need to redesign our spacecraft and building the first skyhooks would be a joint nation-state endeavor.

Interesting high level overview on them here. https://youtu.be/dqwpQarrDwk

Pretty decent pre generation-ship technology.