> disagree with the need to have them at any cost.

I think we can all agree with that. I think a sane position is to return to the level of state support of e.g. the 1960s or 1970s. This worked in a substantially poorer US until we chose to stop doing it.

> There's no reason that grades 13-16 should cost more than grades K-12, so why do they?

This is the key point. Like most things, this is driven by policy choices. The choice is made to achieve certain aims, or to ensure other aims are not achieved. We have the object lesson that subsidized college broadly worked in the US until we collectively decided to stop doing it. We can choose differently when there is political will to do so.

FWIW I would suspect that most of the explicit revenue extraction is less about the types of things you indicated and more about the # of full-fare international students a college is able to recruit. There's a huge difference between a $35k in-state student on financial aid and a $55k student who will pay cash.