There is a reason for this, those places are so small
Kind of, this however ignores populations which is a far bigger factor in the type internet one can acquire.
Regardless, even with this it wouldn't account for the vast differences. What does is the fact that in certain cities in the US owning a connection with a speed comparable to those found in wealthier Asian and European countries is illegal (consequence of cronie capitalism), being unable to expand to certain areas because the courts rule having the ability to set up a superior network as an unfair business practice (again cronie capitalism), and major ISPs in the US utterly uninterested in operating outside of the regional monopolies they have set up.