The Destiny calls us back because its mission is still ongoing. Somewhere out there, in the hypothetical canon of our hearts, the ship is still flying. It is still refueling on blue stars. It is still recording data for a race that no longer exists.
What makes the Destiny fascinating is its indifference to its crew. The Atlantis was designed for comfort; the Prometheus for control. The Destiny doesn't care if you have air, power, or food. It cares about one thing: the signal.
Let’s address the elephant in the observation deck: SGU was dark. Colonel Young was a leader having a nervous breakdown. Dr. Rush was a genius sociopath. Chloe was turning into an alien math equation. And Eli? Poor, brilliant Eli was just a kid who wanted to play video games and got stuck playing survival horror instead.