Do you have any actual evidence of this or is this just more parroting of vibes based history?
Most of the people I know who say things like "School didn't teach me X" were just not paying attention. Turns out, if your society doesn't care about or value education, kids aren't going to pay attention.
Like, some states definitely have mediocre education in a lot of ways, but people will say shit like "Why didn't school teach me how to balance a checkbook" as if school didn't teach them basic arithmetic and the ability to read a single paper of instructions included in your checkbook by middle school.
Or you have people saying "Why didn't school teach me how to understand a loan" as if they didn't learn algebra and how to plug a couple numbers into a calculator right next to me in class.