Most US states are not global superpowers with hundreds of millions of citizens.

The scale is completely different. Economics do not simply scale up and down, the math changes drastically when the numbers get bigger.

>The scale is completely different.

Yes, the scale is different. This means that the debt problem can go on for far longer without being apparent. It can even be put off until the current slate of politicians are out of office, until they're dead of old age and beyond accountability. Scale can hide things, by making them so big your field of vision doesn't allow you to see it all at once.