IMO the biggest problem with the post is that it is ignoring that natural world completely.
We can't colonize mars, not because it's far away and hard to get to (although those are problems). The real issue is that we don't really understand our own biosphere enough to build even an imitation one somewhere else. The ISS is orbits so close it's barely out of the atmosphere. It's still well protected by the Earth's magnetic field, and gets regular deliveries of food, water, spare parts, etc. Every time we've tried a closed biosphere (biodome?) on earth, it has failed.
The bigger Earth's population, the shorter the timespan we have before we can realize we screwed up somehow (i.e. overusing artificial fertilizer, emitting too much carbon, etc.) and having to urgently fix it or the whole planet is wrecked. If we had a "planet B" it wouldn't be so urgent. If we knew perfectly how the ecosphere worked, we wouldn't screw up. If we had "save points" and could just load them if we screwed up, then we could run closer to the edge and go back if we messed up. Unfortunately, this is the only planet we have, and we still don't know how it all works. Because of that, we should really run with a much lower population so that when we inevitably screw up there's a buffer to protect us while we adjust.
What do you mean by "end up broke"?
Do you mean you're going to lose your job in a few months?
Do you mean that you currently have no source of income and you project that you'll hit zero in a few months and won't be able to find a job?
Do you mean that you're going to be declaring bankruptcy because of debts and will have to start over?
These are all different situations. If you don't have a job and don't think you'll be able to get one even though you have months to try, is it because you're disabled or somehow unable to work? If so, there are government support programs available in most places. In places without that, people tend to rely on family to support them. If you can't work, can't get government support, and don't have family or friends who can support you, there really isn't any advice we can give you.
If you currently have a job but they're laying you off in a few months, there are often support programs available. It's best to assume you won't get a job, or at least won't get one right away, so you should reduce your spending now rather than wait.
Declaring bankruptcy is completely different. Often when people do that, they still have a job, it's just that their debts are unmanageable. In the US this is often due to medical debts. You may have a job paying a decent wage, but you simply can't pay down a million dollars in medical debt. That's a different kind of situation, because you still have a job, you still have money coming in and going out. The problem is often that you suddenly have to do without credit cards, you can't get a car loan, etc. So, in that situation the trick is more about how to switch to using cash and debit cards and to build back a good credit rating over time.
If you're truly going to hit zero money in a few months, you need to act as if you're basically at zero money now. If there are food banks nearby, start going there and learn how they work. Watch every single cent you spend and cut off your spending ruthlessly. No subscriptions, no luxuries, etc. If you rent and you expect you're going to be evicted, start selling off your stuff. Better to part with it now and get some money rather than getting locked out and having the owner throw it all away. If there are public libraries nearby with Internet access, figure out how that works so you can still get online.
Also, maybe you can move somewhere else before you hit zero. I don't know what your situation is, but maybe there are places with a dramatically lower cost of living where you can get by for longer. Maybe there are places where you could find work. It's best to make that decision early rather than be unable to make it once you hit zero.