Plenty of people have lived out their lives while rarely or never leaving their small town.
In fact, that was the default for most of human history.
How is that going to work for your population confined to a ship the size of a small town? It isn't. It's science fiction.
Future generations may grow up in a world of much more limited travel, existing in small areas of '15-minute cities' without cars, minimal access to air travel, living in tiny apartments, and most likely spending most of their time in some sort of metaverse, with very limited food choices. We'll have stopped burning fossil fuels and given most of the planet back to nature, and can't allow the working-class masses the transport/freedoms to access/enjoy/ruin it again.
If that's what the world comes to, it'll be a lot closer to life on a generation ship than the world we're used to today.
Not that any of this solves the problem of humanity having nowhere to go. The trip is ultimately futile since the stars you're going to are also dying.
Some did. Most stayed in their little town for their entire lives.
> How is that going to work for your population confined to a ship the size of a small town?
The same way it worked for small towns before mass transportation was available.
That's true - but they do violate what we know about psychology. You're signing on your progeny to be imprisoned on a ship from birth to death, when you yourself never had to endure that. Think about the sentiment behind the "Okay, Boomer..." memes and magnify that generational hatred several-fold. Someone is going to sabotage the ship and its crew long before they ever reach their destination. That's just how people work. Remember, we're not rational.