You’re right that there are many big differences. Launching a rocket into space could be compared with building a major cathedral back in the day. People did both, but not very often, because those projects are very demanding. Ships were also super expensive, but we built those all the time, so obviously the requirements weren’t quite as high.

Also attitudes have shifted quite a lot in the recent centuries, so losing a few sailors isn’t quite the same as losing an astronaut. Nowadays, safety is taken a lot more seriously which makes the project even more expensive.