I think there's conflating of problems here (at for the moment let's talk about primary school K-12 rather than university level).
There is a fundamental problem with a good percentage of public schools right now, where the previous expectations of child behavior, learning ability, and classroom teaching outcome has been broken. And instead of coming up with ways to fix that, lots of people are trying to patch the holes at the output side.
Unfortunately, public schools have to serve everyone, including:
-- kids who have learning disabilities, which seems to be disturbingly an increasing fraction of the population, which costs lots and lots of extra money to pay for
-- kids who don't behave properly in school, which is a degradation of the expectations and frankly, reflection of the standards of families at home
-- "phone-it-in"ism of unfortunately a large enough portion of public school teachers, who are a combination of not the best trained, and honestly, not allowed to enforce discipline any more due to "equity" and liability rules that govern this now.
And instead of being able to fix these problems, concerned people try to look at the easier thing to "fix" which is to rig the outcome to "look right". Until it blatantly and obviously fails. And disserves a generation of kids in the meantime with their hypothesis about how it was going to work.
That's why you have dumbing down of entrance standards, as well as avoiding standardized tests (whether for the claimed reason of being "inequitable" or the worse lazy reason of "it's so stressful for the kids").
In the meantime, those with the means take their kids out of public school because no parent wants to conduct the experiment on their own kid.
And you then watch as our society generally falls behind other countries that are not yet so rich that they can afford to have kids failing and still somehow end up somewhat ok in life.