My comment only applies to Texas schools; I taught JH English-Math-Social Studies, plus JH and HS Science for 15 years after a career in service and my daughter is currently teaching HS Science, so I stay in touch through assisting her. I went through three iterations of State attempts to incorporate standards and institute competency testing.
The schools have focused so sharply on training students to pass their various "skills & knowledge" tests in various grades that they have lost sight of what many of us call "just the basics". The curriculum has been dumbed down in order to achieve high graduation rates and "pass" rates. Inordinate amounts of time are spent on practicing for these "skills & knowledge" tests, but the students aren't proficient in the basic skills such as grammar, spelling, place value, order of math operations, etc.
I have seen students who, when using a scientific formula that winds up with an answer such as 3/1, have to input that into the calculator to get the final answer. Simple operations such as 10 X 5...they are unable to do it in their head and must use a calculator.
This problem didn't "just happen", but its fruit is people who have a HS diploma, reach adulthood, and yet are incompetent in the skills necessary for whatever job market they wind up in. I did two stints in military training schools, and we had to begin to "dumb down" the training manuals to about 6th-grade levels in the late 70s-early 80s.
Another anecdote...I graduated from HS in 1960. After my service career and miving "back home", I began teaching in that school system in 1996. The English teacher who began at that school in 1961 (the year after I left) told me...in 2003...that she was using 1961 9th-grade-level-English lesson plans for her Senior Honors English classes. That's how much it had been dumbed down.
Your experiences may vary.