I think you mean "oligarchs" for they. I have no answer, I'm just a peasant in today's America. My economic interests absolutely do not align with oligachs'. I expect the oligarchs as a class don't think they'll personally be too handicapped by trade wars, and see some way to make more money out of it. Maybe Trump has promised them fiefdoms in a fragmented and demoralized US.
My specific knowledge does not allow me to say why they aren't (or are, behind the scenes) trying to stop the Greenland nonsense. It seems likely that Trump has promised them a slice of the extraction wealth, or that the oligarchs as a group don't see much trouble arising from a Trump takeover of Greenland, so they're just letting him do it rather than annoy him, or his easily angered base.
My specific knowledge does not allow me to say why they aren't (or are, behind the scenes) trying to stop the Greenland nonsense. It seems likely that Trump has promised them a slice of the extraction wealth, or that the oligarchs as a group don't see much trouble arising from a Trump takeover of Greenland, so they're just letting him do it rather than annoy him, or his easily angered base.