@BelknapPoint wrote: “I’m definitely not in favor of a system where the government has even more direct say in how a person should spend his or her own money. The government overreach and intrusiveness described here borders on tyranny, in my opinion.”
Note that this system is actually child support enforcement, which I understand US authorities tend to be much more draconian about than many other industrialised countries.
The difference to the US is merely the cutoff point: not a fixed age between 18 and 21 according to state law + high school graduation, but an education that enables the child to support themselves according to their interests and capabilities, necessitating a qualification beyond high school. Which can mean finishing trade school at 18 or getting a masters at 27 (Yes, I agree that the latter is ridiculous, but these are cases I have come across). The student has obligations, too: consulting the parents, keeping them informed about grades, remaining in good academic standing and graduating in a reasonable time frame. Once a student has gained their first post high school qualification, the parents are usually off the hook. The student can always keep going for higher qualifications by applying for government aid as an independent, though, the government has a rather harder time getting off the hook than the parents have.