The interesting thing about Parler is that the US government and its laws are neutral to it, but no US corporations wish to carry the liability of serving them--regardless of the money they offer. Legally, Parler could operate but no laws exist to guarantee it can.

If this scenario played out in another business, like a restaurant, then nobody could really stop them from operating. Even if the food supply companies stopped delivering, there is a decentralized network of small farmers and transportation companies that could pick up the slack. No such counterpart exists with internet companies. You're either part of the grid or you're out. Come to think of it, that could explain a lot.