In an international comparisons, USA comes out somewhere in the middled of developed countries - as it always did. And the differences between countries are not that large.

54% of adults have a literacy below a 6th-grade level is simply not a some kind of catastrophe and it does not mean those people cant read. There is this idea that 6th-grade level is almost like not knowing how to read, but that is simply not the case at all.

Hasn't this always been an intelligence thing? I think across all societies and eras we find that generally a a rather alarmingly large section of population is unable to grasp basic written instructions - and that section usually increases to the majority of people, when we start getting into things like an employment contract, or mortgage document.