https://en.wikipedia.org/wiki/Antarctic_Treaty_System
Not that there would be much going on without the treaties, but it would likely be commercially viable for oil exploration or maybe mining.
There are also other reasons. You can't learn about the possibility of life on other planets in Antartica, and seek to answer one of the greatest questions of all time: "are we alone?". You can't closely study another planet in Antartica. You can't be a brave new explorer seeing incredible places for the very first time in Antartica. There are far less new scientific and engineering challenges in Antartica whose solutions will greatly benefit everyone here on Earth. And so on.
Note, these things are true for any next-gen space endeavor in our corner of the solar system. It doesn't have to be Mars, or even just Mars. For example, we could build larger and more advanced facilities and machinery in LEO, while also building a small base on the moon and exploring Mars for the first time.
That's an argument against research on Antarctica, but that's the one thing humans do there.
I think settling Mars will and should happen, but anyone who doesn’t realise it will be thousands of times more expensive, risky and dependent on external support than eg Antarctica I think isn’t really grasping the difference in scale of the problem.
It's hard to imagine there's an economic case for Mars or the Moon while Antarctica remains undeveloped.