If the unit economics look great (my understanding is they're at least fine-to-good), then they should not be taking profit because it is very much in their interest to do capex to grow their capacity so that they can continue to grow.
It's a knife's edge because if they invest too aggressively it could lead to bankruptcy, but so far they've actually been quite conservative and given their unit economics they can afford to pay $$$$ for expensive inference compute (and indeed that's why they've inked a bunch of deals in the past month or two)