Scale... Isn't the USA supposedly federalised states? So each state has a small enough scale to solve its issues, with an added benefit that countries in the EU don't have as easily: a federal government that can work to provide funding, coordination and national-level programs to solve the issues. The closest to that coordination is at the EU level itself which is much more complex and less powerful than the federal government of the USA.
I really dislike when American exceptionalism gets to the point of brushing away any kind of role model that could be used as an inspiration to be adapted to American needs as "it won't work because we are different". Guess what, every nation and society is different. Learn from others what worked, adapt to your local needs, that's how progress works.
The USA has the largest economy in the world, there's plenty of money that other countries lack for solving social issues. The main issue is allocation, American society does not think that solving social issues is worthy enough so you don't invest in it. After experiencing all the side-effects of such negligence them comes the exceptionalism excuse, that the scale is different, that X, Y or Z are hard because of A, B, C, so on and so forth.
It's just an excuse, a lame one at that. Yeah, Nordic countries don't have a large population, as a whole there's around 28 million people across the Nordics (Finland, Sweden, Norway, Denmark, and Iceland), with around US$ 1.8T of GDP. Texas in the USA has 29 million people with US$1.8T GDP in a much smaller area than all the Nordics combined, with better weather, why the fuck can't Texas be like the Nordics then?