Parents, kids, and time

Not too long ago, ABC's 20/20 ran a feature by John Stossel that, among editorial remarks such as "American kids are stupid," compared American schools to foreign schools. Stossel claimed that American students perform worse on international tests the longer they stay in school. American fourth graders perform the same or better than most international students on basic math, science, and reading tests, but somewhere between fourth and twelfth grade, American scores drop drastically. Stossel concludes that it's because American schools, as he eloquently puts it, "are bad."
I have an alternate theory:
I was picking up my son from the after-school program a couple of days before his kindergarten graduation, and I witnessed a pretty sad scene. A little boy was crying in the arms of the head teacher because his parents could not attend the moving up day celebration. In the meantime, my son ran across the classroom to greet me, and the other little boy cried just a little harder, most likely from envy. It turns out this boy is often the last to be picked up because both of his parents work late. Most of the time, their work schedules allow one to be home in the evening fairly early, but on occasion, their shifts overlap leaving the little boy in the school's care for 12 hours.
I can remember how my son reacted a year ago when I picked up a night job. I worked three nights a week as a researcher for a phone company. I did it to pay for a second masters degree in communication, but it took its toll on my relationship with my son. I had twenty minutes twice a week to play. That's all. This went on for six months. During that time, even though my wife was there to play games in the evening and read to him at night, he was angrier, got in trouble more at daycare, and cried occasionally to his teachers just as the little boy did in the after-school program. As soon as I graduated with the second masters, I quit the job. Money was tight, but I didn't care. My son needed me to be there, and within weeks, his behavior issues, anger, and sadness disappeared. He was back to his happy self because I was back to being a parent.
People are quick to blame schools for the deficiencies American students show when compared to foreign students. While any given school can always use improvement, I think the root of the problem is the amount of time American parents spend at their jobs, away from their children, compared to foreign parents. According to "Porch magazine" , Americans exceed "Japan by 137 hours a year and Germany by 260 hours" in the amount of time spent working, and spend "40% less time with their children than they did in the 1960's." Do you think this may account for some of the problems American schools are faced with today?
I had to make some tough decisions to spend more time with my son, but after seeing my son's classmate who spends much of his life wishing he were with his parents, I know I've made the right choice. Maybe American parents should think less about blaming others for their children's social, emotional, behavioral, and academic difficulties and think more about how much their work schedules are contributing to the problem.