>Maybe some much more advanced civilization would do one star shot, found one colony, and be like awesome now we are in two solar systems and that’s enough.

There are over 100 billion stars in the Milky Way alone. Your statement might be true for 99% of civs, yet the remaining 1% are still gigacolonizers.

>It’s probably a lot easier to terraform terrestrial planets or build a living Dyson swarm of Stanford toruses than build a starship. Certainly easier than building more than one starship. The human race could probably expand for hundreds of thousands of years in this solar system before we would ever feel any actual pressure to go elsewhere.

If you're Kardashev type 2, what are you going to do with all of that energy anyways? Why not give your Stanford toruses sublight engines, and turn them into superfast interstellar cruise ships full of amenities? Lawnchair Larry said it well: "A man can't just sit around."