If computing ability continues to expand in its current fashion, it will be trivially easy to create entire virtual Earths as simulations by the 24th century than to actually settle other planets.
So much easier, that a lot of people (such as Elon Musk) believe the "simulation hypothesis." That is to say, given a future Earth civilization could run hundreds of different simulations of Earth over time, chances are based upon the law of averages we are not IRL, but in a simulation.
A fun theory that I wish no one had thought of.
I've got a young relative who had an overdose-induced psychotic break a few years ago, and now believes that literally, and that the aliens in charge have the whole simulation set up to fuck with his head. He refuses to take anything or anyone seriously, including his doctors, because "they're not real, so what does it matter?" His parents are scared shitless because he doesn't care if he lives or dies.