[imoverclocked]

... which begs the question of who would really arrive at the destination. Our own civilization starts to rebel at things that were heralded by the previous generation because the current generation doesn't remember the problems that were solved. In two generations, the humans that remain might not leave the ship at all despite having a whole planet (or multiple) to inhabit.

[bluGill]

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

[Ekaros]

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.

[carpo]

I think you'd have to manufacture a culture, with rituals and habits designed to keep people focused so that the meaning of their lives was tied to the end-goal. It would make a good story :)