Yes I think that if SpaceX succeeds with Starship and starts building the colony as they hope, that 50-200 years from now the settlement would be at least partially self sustainable (can self sustain in an emergency).

There are many reasons an independent settlement makes sense. Earth could get stalled in political deadlock, have a nuclear war, or fall under the control of autocratic regimes.

But there are direct benefits to humanity even without these worst case scenarios. Independent thought and political control at a time when the countries on earth become ever more intertwined (China’s Belt and Road) will probably serve some benefit in our future.

And then regular rockets between Earth and Mars would pave the way for asteroid mining, which would allow construction of massive solar energy harvesters.

That’s 200-500 years out but if we’re capable of starting now I’m not opposed to folks trying!