The big difference between the Nordic countries and the U.S. is the wage spread. The main reason is that the lowest-paid workers in the U.S. have very low incomes, indeed. The minimum wage there is equivalent to NOK 45 per hour, and that is the actual wage for many millions of workers. The minimum wage in Norway is twice as much, NOK 90 per hour, and even that level is regarded by LO as too low.
But there is quite a difference between earning less than NOK 100,000 per year and almost NOK 200,000 per year. It means that, in the Nordic countries, workers earning the minimum wage can have a decent standard of living. But their counterparts in the U.S. normally can not; they need to have two or three jobs, social assistance, or some other kind of support.