A child has his parents. An adult has his friends and neighbors. The situation couldn't be worse. This arrangement keeps most people seriously misinformed. This is a real problem in daily life.
Teachers can only know so much.
Even if we were to develop a race of omniscient teachers, we would not solve our problem. No teacher has the time to answer every question that every student has. One might think that in a large organization the experts might be available to the people in that organization who need their expertise. But this is usually not the case. The people who really need the expertise, who have the most to learn, namely, the newest and least important employees in the organization, have the least access to the experts.