Critical thinking

No child left behind already stripped it from public education...

Because there was zero incentives for a school performing well. And serious repercussions if a school failed multiple years, the worst schools had to focus only what was on the annual test. The only thing that matters was that year's scores, so that was the only thing that got taught.

If a kid got it early. They could be largely ignored so the school could focus on the worst.

It was teaching to the lowest common denominator, and now people are shocked the kids who spent 12 years in that system don't know the things we stopped teaching 20+ years ago.

Quick edit:

Standardized testing is valuable. For lots of rural kids getting 99*'s was how they learned they were actually smart and just for in their tiny schools.

The issue with "no child left behind" was the implementation and demand for swift responses to institutional problems that had been developing for decades. It's the only time moderates and Republicans agreed to do something fast, and it was obviously something that shouldn't be rushed.