Those types of parents are not seeing that their kids get an education even today, with all the welfare and gov't provided support. Seat time is not education.
You'll always have dregs in society. Why drag the rest of society down to the lowest level just because there are a percentage at that level ? Why not end the charade of educating those who don't want it/don't appreciate it, and set the standards higher for those who will work at getting an education ?
If education was cheap, and it had value in the eyes of society, even the dregs and the children of dregs might be motivated to try.
You don't appreciate what you get for free nearly as much as something you have to work for. Think the "Law of the Commons".
Indeed it's not. Which is why I propose a system in which tax dollars are only paid out AFTER some minimum results are achieved. And those minimum results, while very low, are still higher than what 50% of public school students are currently achieving at huge cost to the taxpayers.