Even so, they are united States (as opposed to, say, Australia where the so-called "states" are for all intents and purposes merely administrative subdivisions

Even so, they are united States (as opposed to, say, Australia where the so-called "states" are for all intents and purposes merely administrative subdivisions of the continent, and could be remade by passing a law in the federal parliament) This isn't really true. The fundamental setup of the Constitution of Australia is that the separate States retain their existing power to make laws and enforce laws on essentially any matter (with some very specific carve-outs, like the states may not coin money, raise armed forces or try to impose a tax on the Federal government). The Federal Parliament is granted the power to make laws only with respect to an enumerated set of heads of power. This is, for example, why the Federal Government was able to overrule voluntary euthanasia legislation in both the Territories, but cannot in the case of the State of Victoria. The vertical fiscal imbalance mentioned elsewhere certainly is an issue, where the State Governments are responsible for most service delivery but the practical revenue-raising ability of the Federal Government is significantly greater. This results in the Federal Government using 'tied grants' to influence State policy, but it is my understanding that a similar thing happens in the US as well (for example in the case of raising the drinking age to 21). In terms of remaking the States, the Constitution specifically disallows altering the limits of a State without the consent of that State's Parliament and passing a referendum of that State's voters.