Except that's the problem, schools should stick with whatever works until there is evidence that something else works better. Back when schools taught the 3 R's, you didn't have many kids getting out of high school functionally illiterate. Then, you had the big liberal social experiment when schools taught kids to feel good about themselves, nobody ever failed and everyone got a trophy just for showing up. That has screwed up our country to no end. Had we just stayed with what worked, we wouldn't be in the mess we're in now.
If the customers (parents) don't like this the way a certain school, they can take their kids elsewhere... That's the beauty of a private system that can't exist in the public system... Someday the exact same argument will be brought up about this universal healthcare, and it'll be just as valid!