I’m guessing it is how Earth was. But that is just my guess and I have no information to back it up. You would think if it was how Earth would end up there would be more to it other than soil.

I think that if we are thinking of a long-term runaway greenhouse and environmental catastrophe - we are looking more towards the planet Venus for a likely planetary atmospheric template.

Earth, in the past, was much more covered with water. The very early stages of planetary formation include vast bombardments from space with meteors and so on which cause great volcanic and geological cataclysms.
When this settled down on Earth, large oceans formed from the water delivered by asteroids and meteors.

I guess Mars could be a possible future state for Earth after the ravages of environmental disaster.

On ”Life on Mars” - I think it must be inevitable. The self-organising complexity which birthed life here on Earth is a physical principle of the way matter does stuff. Life will likely have popped up as soon as possible in squintygazillion different eligible environments, both planetary and non-planetary. Amino acids (the basic building blocks of life as we know it) have been found in vast clouds in interstellar space through spectroscopic analysis. :)

What troubles me is that once the interplanetary transport problem is more happily resolved, some bastard multinational will rush off to try and capitalise on the resources of this distant world. I see the Universe and I see beauty. A future multinational company will see the Universe and see only real estate.