It’s easy to get on the boat, it’s hard to get off the boat, it means there’s no end to it until someone dies.

It means that when you start to do something, don’t underestimate the difficulty of the thing, and have patience and perseverance to face difficulties and challenges. "Easy to get on board" means that the threshold for participating in something is relatively low and easy to enter. "It's difficult to get off the boat" means that during the participation process, it is not easy to achieve a certain goal, and it requires a certain amount of effort and time. "No one dies" represents continued existence and constant trying. It means that as long as you don’t give up, success is possible. "It's not over yet" means that things are not over yet and you need to continue working hard. The whole sentence means: It is easier to participate in a certain thing or process, but it is more difficult to withdraw from it or achieve a certain purpose. At the same time, as long as people don't give up, this thing or process will continue.