It's expensive, but not nearly that expensive. Starship has charged $90m so far. That's including a healthy profit I'm sure. SLS is ridiculous in how much it's cost. It's not a good comparison for how much it would cost if this were a normal occurrence.
Starship is certainly far more expensive than it would be too, because there's a lot of technology that has to be developed, and that R&D has to be paid for. The more launches there are, the more spread out that cost becomes, and the cheaper a launch costs.
That's the unmanned cost, but manned should be similar eventually, and potentially cheaper if it's common enough. It's a crew size of 2-4, so it's 22.5m/person. Still far more than Antarctica, but essentially zero compared to the cost you gave.