Obligatory Sold a Story podcast link.
I can't help but feel that a lot of this is deliberate, the end result of decades of dismantling the public education system to further divide kids into the upper class in private schools, religious fundamentalists in home schooling, and everyone else abandoned to keep the population uneducated and in worse economic precarity.
Somebody please tell me that the kids are alright 
I think at a base level of "Can read and communicate concepts and ideas" it's true that the USA is literate but in the sense of having strong reading comprehension and the ability to synthesize/critique based off of that comprehension, we absolutely suck.
I see plenty of long winded heavily overanalyzed power posters on Reddit. But when they treat the CIA Factbook as gospel and denounce Seymour Hersh as Fake News...
That's not a comprehension issue. It's a trust issue.
Critical thinking issue too, imo
Garbage in, garbage out. Critical thinking only gets you so far.
I'm saying that learning to distinguish garbage from not garbage is an important facet of critical thinking
Yes. But those same skills, absent reliable information, can be subverted.
What you're describing is ultimately just an understanding of institutions. Having a very well refined understanding of libraries doesn't get you useful data if you're trapped in the fiction section.
Ask Decartes how that works. "What am I able to know is true?" is a very fundamental philosophical question without many bulletproof answers.
Fair enough, thank you for explaining where you're coming from, have a good day