Parents are biased due to survivorship bias. They go through it. Because they are rich afterwards, they have children, and they think their children can be successful too under a similar system. Especially since the parents clearly had to succeed greatly to have enough money to raise a child, the child often thinks that they are way below the parents' capabilities, which is a form of sampling bias because the child hasn't really seen other less fortunate adults. Instead, they often get blamed for not utilizing how "fortunate" their position was. Plus, they already forgot most of the bad and boring stuff about schools: Schooling amnesia
Additionally, there is little power from individual schools to change out of poor PR, and the fear of experimenting with a standard that very few other schools, if at all, have done. Rather, even if, for instance, my secondary school did change, upper secondary school was still going to be almost entirely examination-focused because universities need those qualifications! Any large deviation (Which is needed to avoid the Prussian Stupid System) is seen as trash by the higher body (No public exams? No unit. No uni? No job.) Unfortunately, it's the WHOLE SYSTEM of merit that is infected with such ideals. Even if you KNOW it's bad, I hate to say, you can do very LITTLE to the BIG system, but to survive through it (and contribute even further to the survivorship bias).
Even more, kids have no voting rights. Neither do teenagers. Little research is done on teenagers due to legal concerns (Problems of research), so things like DSPS in Teenagers tend to be dismissed as minor concerns. And then there's EVEN a fear of the smaller tribe (which is well documented in sociology), which means that society cannot really imagine those who did not go through an education and preserved their freedom as being intelligent. This is possibly due to media bias, or algorithms that TikTok/YT scrolling, etc., and video games, are all you teenagers will do other than school, and these tend to be dismissed as inferior. Rather, if there's agency, there's a way, and this can be seen as an attempt to reclaim their freedom outside of school hours.
And in a classic logical loop, Education system ultimatum occurs, only this time we've already lost. See there for more details.