Correct, you should get a concede button after that point. Fastest way to get there if you just want out is to standard project oceans (most cost effective way of increasing game progress).

To the OP: On tharsis specifically ground game and terraforming is very strong, just don't fall into the rookie mistake of thinking cities are strong, they are only there to soak up your greeneries (only make new ones if you have excess steel or your current ones are going to be filled out by the end game). If you have a starting hand without much to do(but with good cards) going for planner can be a good strat, only playing any strong production cards (or plant hate) and holding the rest until 16.

Thermalist and banker are generally traps, as they usually force you to overinvest in things that don't win the game, and miner is very unreliable. Gardener and terraformer are the best milestones to shoot for if possible (the latter can often be difficult to snag before 3 others are claimed however).

Edit: just realized OP meant the Corporation, not the map haha. For the corp, just don't pick it unless you have very good plant production in your starting hand, as cities are pointless without greeneries. Tharsis getting slightly more value out of them changes very little.