Yes, there have always been good and bad parents but many things are much more difficult about teaching then they used to be. There are more parents who don't care or are too busy to care. Kids don't want to be taught, they want to be entertained. They have come to expect instant gratification and that is not what school is about. I have so many kids constantly complain that the subject is hard. I ask them when anyone told them it would be easy. I've dealt with so many great parents who support the school and the teachers and and almost 100% of the time those kids do well. I've also dealt with parents who couldn't be bothered to care about their child's education. Those kids almost always do poorly. I've also had the joy to dealing with the "blame the teacher" parent who thinks their child does nothing wrong and the teacher is just picking on them.
Does this mean that all the problems with education are the parents' fault? Of course it doesn't but a teacher can only build with the raw materials he or she is given.