> people struggle to deal with leaving the Blue Dot behind, esp. when they see footage from the earth, rainforests, etc.

5 generations on, the people on the ship didn't leave anything behind. They were born and will die on the ship, and that will be their baseline. Even in places where life is the hardest here on Earth, in the middle of scorching or freezing deserts, people don't get depressed en-masse seeing nice pictures from elsewhere.