I found this podcast from this 
post:
I subbed today for a 7th and 8th grade teacher. I’m not exaggerating when I say at least 50% of the students were at a 2nd grade reading level. The students were to spend the class time filling out an “all about me” worksheet, what’s your name, favorite color, favorite food etc. I was asked 20 times today “what is this word?”. Movie. Excited. Trait. “How do I spell race car driver?”
I've only listened to one episode so far, but it's really well produced, seems well-researched and very well put together.
From what I gather so far, the ways that the American public school system "teaches" kids how to read is not only completely wrong, but actually saddles them bad habits which fundamentally hinder their reading comprehension.
A huge swath of American adults are functionally illiterate, and I think I'm starting to understand why.
So in other words it's not really also rich kids
what I mean is that rich school districts were also using this method. there's a bit in the podcast where rich parents in one of the wealthiest neighborhoods in the US were going to the library to ask where they could get materials to teach their kids how to read.
Yeah my MIL used to be a public school teacher in a district that no one would ever call poor. Not the richest, but definitely not poor. For the last several years of her career all I ever heard from her was along the lines of "what the fuck am I supposed to be doing again? I have a room full of 9th graders who can't read." No idea what method they were using in the earlier grades, but well off suburban districts are definitely pumping out illiterate kids as well.