I'm speaking to what I know.

And, honestly I think that this is the way that secondary education is designed in the US.

You use the term "functionally illiterate," but I think that we have to be very careful here.  If that phrase is to have any meaning, it has to be connected to some sort of expectation of what students should know. And, the expectation seems to be a very basic level of knowledge.

Part of the problem is that I think there is a tendency to want to have a very broad (in subject terms), but not very deep education at the secondary level.  If you really want to know what the standard are for high school education, look here.

This is one state, but is probably pretty typical. Even this is misleading, because students think know that all they really have to do is memorize.  Most high school tests are multiple choice, and that form doesn't give itself to asking questions that actually answer whether a student understands material.

And, in the end.  Students just don't care, because it's not like there are consequences for being a defiant little bastard and just refusing to do any sort of homework.  If schools try to enforce standards, wealthy parents will just revolt.  

It may be that this is the problem.  Schools aren't expected to enforce standards, and there's pushback if they try to do so. So students grow up in an environment where there are few, if any, expectations.

The very idea of public education, that the State should be determining what your children learn is somehow suspect.  So you get charters, etc....  Which promise to improve the situation, but make it worse.

And now I am being entirely jaded.

And I'll give my consent to any government that does not deny a man a living wage-Billy Bragg