This is a popular trope heavily marketed in certain circles but it’s not even remotely true and it’s deeply disrespectful to the teachers working in an underfunded but critical position.
Beyond the obvious politics, the other thing to remember is that student performance very closely tracks the parents’ socioeconomic status. This is most known for explaining the gaps on international testing but it also leads to people misinterpreting school data and drawing the wrong conclusion. My son’s school is notably bimodal because it has both recent immigrants who tend to be poor and affluent professionals, and people sometimes look at the averages and conclude that the school is bad when it’s really just rediscovering that being poor in America sucks.