>Greenland currently receives significant support (about $10000-15000 per capita yearly) from Denmark. So it is not clear how the country would run without that.

Greenland absolutely positively cannot run without outside subsidy. Pacific islands (barely) function as independent countries because their tiny populations are commensurate with their small areas. Greenland's 50,000 people live on an island three times the size of Texas.

Currently that subsidy comes in the form of €600 million in annual funds from Copenhagen. Now Washington has emerged as a potential outbidder.