[andsoitis]

Apparently not!

An opposite question is interesting: why not abolish state governments and only have the federal government? I haven’t thought about it deeply so don’t have a strong sense that it would be better than the status quo, though I suspect it might.

[fallingknife]

Centralization and size comes with inefficiency and slow decision making. It also comes with economies of scale. For something like the Medicare, the economy of scale dominates and it makes much more sense to be federal. When it comes to running schools, there really isn't much economy of scale so it makes much more sense to run it locally.

[gottorf]

Economies (and diseconomies) of scale exist, of course, but aren't central to what is the responsibility of the federal government and what is the responsibility of the state governments. That, of course, is laid out rather plainly in the founding legal document of the country.

[int_19h]

The more people are ruled by a single government that is ostensibly a representative democracy, the less representative said democracy actually is. This should be rather evident - you can't grow parliament size indefinitely if you want it to continue functioning as a deliberative chamber, which in turn means that every parliamentarian represents more and more people, which in practice means that they don't represent them well.