The Earth and the ISS are the only two places in the solar system that a human being can do anything without wearing some sort of space suit. The ISS can only provide this environment thanks to a lot of external logistics support from Earth. There are exactly zero self-contained and self-sufficient environments off Earth. The most inhospitable environments on Earth are orders of magnitude easier to survive in than even the most inviting environments in the rest of the solar system.
Even if we managed to get some sort of colony established on Mars or the Moon it would take vast sums of money and a lot of time to get them to a point where they could be considered even remotely self-sufficient. We have a difficult time building entirely self-contained and self-sufficient environments here on Earth let alone in deep space.
Keep in mind self-sufficient doesn't mean a bunch of Martian or Lunar agrarian colonists in some steady state. It means having enough advanced industry to build equipment necessary for survival of subsequent generations. If Martians can't build themselves new backhoe loaders, space suits, and semi-conductors they're not going to survive Earth getting wiped out.
Thinking that we're going to colonize the solar system as "insurance" against something happening to Earth is a fantasy. Colonizing space is absolutely nothing like colonizing anywhere on the Earth. Columbus and Cabot had breathable air, drinkable water, and edible flora and fauna at their destinations.