Curious why population is even a factor here. If it legitimately should be... why not compare states of the US with states of the EU? (Seems a roughly equivalent thing to do)
Bigger and more diverse countries have a wider variety of political issues and priorities. When was the last time broadband even registered as a political issue in the news, except in the context of some other more important political debate (urban/rural, racial disparity, etc.) And in the US, construction of infrastructure is mostly a municipal level issue, so its both low priority and varies dramatically by state.
Here in Maryland (which is a small, politically homogenous, rich state, just like Denmark), most of the state has fiber or gigabit cable and broadband speeds are very fast: https://www.webfx.com/blog/internet/fastest-internet-connect...
> In fact, the next state on the list, Maryland, is nearly tied with Denmark for the second-fastest Internet speed on Earth.