Their kids will leave the spaceship though. And some dare devils of their generation.

I doubt that number would be sufficient. Such ship would have to be very stable society. So getting enough people to harshness of unsettled planet is very tall ask.

I believe historically it was either for profit, which there is unlikely to be much in medium term. Or because the new place was expected to be better. Mostly due to resource constraints. But generation ship should be quite optimal. And well outside magic level tech there is not much to do on empty planet.