Didn't the first colonist almost starve, if not for the food they got from the natives, as celebrated during thanksgiving?

There are no natives on Mars, neither is there breathable air, soil, livable temperatures or potable water.

So you need to take all of that with you, which is impossible. Or instead take entire industrial supply chains to mars to create those essentials. Which is almost impossible but perhaps not entirely.

Anyway, it will cost endless resources to kickstart Martian colonies.

Trillions of dollars at least.

Can we spare that? Perhaps but we will need to tighten the belt somewhere.