I was a disruptive child and my parents were the opposite of people who didn’t give a shit. Both of them highly valued education and spent plenty of time with me. they just had to contend with a child who wasn’t well behaved at school and it was genetics more than anything they did. They spent thousands of dollars on therapists and medicines and it didn’t help that much. Luckily for me, puberty seemed to turn things around and I ended up doing well in high school and very well in college (at a good school). Now I’ve got two little trouble makers of my own and it’s pretty obvious to me where they got those genes from.
I agree that dealing with problematic kids is a pain in the ass for teachers and I do try to thank them when I see them, and I even agree that parenting is often the issue, but a lot of it is genetics and luck.