According to Jeff Bezos, there are a bunch of problems associated with colonizing other planets that do not exist when it comes to nearby outer space.

Other planetary [which we could attempt to colonize] aren't that big when compared to Earth, maybe a doubling of surface area at best. Considering how far they are, that's not that useful.

Round trip times are a significant logistical problem. Trips to Mars, for example, are on the order of years, and launch opportunities to Mars only occur once every 22 months.

Lastly, other planets are far enough away to do real time communications with Earth, limited by the speed of light.