Won't dreams stay dreams? There's literally nothing there, why go all that way? The distances are so incredibly vast. It seems like we ought to be content with staying put.
There was a time when there was nothing (European) in the entire New World. There was a time when there was nothing known (to the US) about what was in most of the Louisiana Purchase. There was a time when there was nothing (European) in, say, Ohio. And then Nebraska. And so on. There was literally nothing there? Why go all that way? To see what was there. And then to make something there. [Edit, because I'm rate lim…
No there wasn't. There was a whole continent of untapped resources.
You can argue that the solar system is a lot of untapped resources too. Harder to extract than sailing a piece of wood across an ocean growing some food, and killing the people who are already there. Harder than colonising Antarctica or the surface of the sea too, but there are resources - not just minerals but solar energy too.
But interstellar space? Beyond the Oort Cloud? There's no evidence of anything other than perhaps some very sparse dust. That is nothing, and (jokes aside) completely incomparable to Ohio.