It may be the child's association of reading with having been cuddled and read to as a toddler. Some researchers say there's even a benefit from reading to a child before it is born. It may be a meaningful discussion about what's going on in school, and supporting the curriculum with a family trip to the library, museum, state park, the backyard garden, encyclopedia or Internet. Children notice if their parents attend teacher conferences, PTO and other school events, or volunteer in school. For most of human history parents were the sole source of children's education.
Some parents still prefer home schooling.
It's teacher involvement that's the new innovation. The pressures on today's parents take them away from children. Some are single parents. Adult supervision falls to the television set. Education to the teacher.