$1:
they'd rather have their kids grow up uneducated and marginalized
Try working on or near a rez. Beginning in the earliest primary years you have half the class showing up sporadically, and the parents just don't give a shit. They never show up for parent teacher interviews, meetings with speech therapists or consults with the resource department. There are kids with court orders to attend class, but they never show and it's impossible to locate the parents. We have kids in Grade Six who are shaky when it comes to the alphabet and its associated sounds....numeracy....forget about it.
Those kids who do show promise(about 10%) are often unable to learn because the other little shits are so disruptive that it's impossible at times to conduct a class. They also face taunting for their desire to be better than their 'peers'. Out of 45 kids in Grade 12, only six are going to graduate this year. One is my own, one other is another teacher's daughter and four are adult students of mine.