>Most parents just watch TV, stare at their phones and don't want to be bothered by anything that requires effort

This lazy "answer" to every parenting problem makes me roll my eyes nowadays. It's the equivalent of an umbrella hypothesis, a convenient excuse for not having to consider things in-depth, further justified by seeing parents when they are taking a break and assuming they're always like that.

Not only that, but it's a dead end for societal policy. Even if a person actually believed parents deserve the most blame for kids' educational outcomes, that person should recognize there's no real way to influence this (short of dystopic levels of forcing kids into foster care). They would then find the second most blame-worthy cause to fix.