You might think scores are flat or declining, but this is not acccurate. There is a large gap betweeen what is tested and what is "required" to be taught. State curriculum websites are more of wish lists than actual curriculum guides. They are typically "a mile wide and an inch deep". It is impossible to cover all the material with any fidelity.
And then there's the test. What will be tested and how will the questions be constructed. I can teach you an simple concept like Ohms law and then have a test writer construct a 4-paragraph question with multiple graphs about resistance and current followed by 3 tricky multiple choice questions and there is a good chance you will screw it up.
This is the way I see it. Many schools are "good" and server their communities and students well. Schools is less desiriable communities are understaffed, under-resources, have large staff turn over and are the poster child for school reform and waste.
Some politicians look at education in the same manner that the look at defense spending... LOOK A BIG PILE OF MONEY... HOW DO I FUNNEL IT TO MY FRIENDS? The trick is to constant "reform" schools until they system can no longer respond to change and shows up on test scores as a flat-line or negative grow. Then you can shout, "LOOK ALL THE SCHOOLS ARE FAILING, HA! WE TOLD YOU!" we need an unlimited voucher program. People should be free to choose any school.
What will happen is that schools will accept the vouchers + tuition and education will become stratified. Everyone will pay as much as they can to send their kids to a "good school" while the poor concetrate and languish in the left-over public schools.
As a parent, I like the idea of vouchers and being able to send my kid anywhere, public or private. The voucher could be used as a coupon for that really expensive private school. As a citizen in a democracy, I shudder, thinking that our democracy depends on strong public institutions like public schools and without them our society will crumble. I also believe history bears this out.
What is the solution? ..... ask me and I will share my education policy. :)