[BlueTemplar]

Yes, exactly, while the average USian might still keep up with the rising costs of healthcare,

(and in fact being the cause of rising costs because that is where they are going to spend their disposable income),

the median USian will not.

Partially this also comes from statistical effects that aren't scale-invariant :

Countries with more people are more rich (including per capita).

Countries that are richer are more inequal.

Countries with more people are more inequal.