Really? Seems like building a manufacturing capability on Everest or Antarctica or a Saharan dune sea would be easier in every single way.

You're right, it would be easier in every single way.

It would also be different enough that it's not a useful or meaningful comparison. You might as well say "bake a cake while standing on stilts, then we'll talk".

By the way, humans have been mining, and on-and-off purifying, iron from the Saharan dune sea for a thousand years. https://en.m.wikipedia.org/wiki/Zou%C3%A9rat

While there is a lot that could be said about this at the object level, the correct answer is “so what?”