Do kids with involved parents have access to more scholastic potential because their parents cared? Almost certainly, and that's a good thing and we should harvest it, not attempt to force something that is not going to work.
Now, numbers aren't that easily available. And maybe parents caring has a permanent effect that lasts even once they are gone. Real life is far more complicated than my example. But it shows a very simple possibility of why measuring potential while ignoring environmental failures can lead to a sub-optimal ranking.
What an absolutely ridiculous thought. Literally our entire personality, our study habits, and our grit come from our parents.
When a kid's academic achievement is significantly caused by their parents constantly putting daily active pressure on them, the removal of that pressure can cause them to completely fall apart.
Take a simple example of waking up in time for class. You can have a college freshman who was taught by their parents to be up on time. You can also have a college freshman who always depended upon their parents to wake them up and is thus oversleeping.
The former seems more in line with the true potential, while the latter is a temporary benefit from parents. A kid who taught themselves how to wake barely on time will do worse than a kid whose parents makes sure they wake up with time to spare when parents are present, but if the parents don't instill the values of waking up on time to the latter child, then in college the former one will do better.