A third of the revenue in greenland is the danish sending money to them. If they want to become independant it will be a lot of work. Cut their legal systems off of denmark, loose all the danish funding, loose the danish military and a lot less danish people will move there(because a lot of jobs need education that is simply not available in greenland). Also the only place that is properly connected to the rest of the world is nuuk with a population of 20 thousand. Im not saying its not possible just that iceland did it and they played on easy mode compared to greenland. By the way they are also in a bit of a problem because they rely on nato for their whole military and nato is pretty unreliable nowadays. And we are talking about a us(technically) invasion anyways so nato wouldnt help greenland. You just dont get how small the population of greenland is.