There is still a great need for smaller, more focused classes at the university level. From your comment, it seems you haven't had the pleasure of one of these, because you are certainly expected to learn on your own. The face-to-face interaction and being around other people helps you learn different skills (presenting research is an important one in the sciences), and having a smaller (6-10 students) class allows for greater depth and discussion to be achieved. If you're still in college, I highly recommend taking some classes.
And in graduate school, nearly all of your classes will be like this. So no, it's not a necessity just for grade school (unless you want to make the case that graduate students are bumbling morons and akin to 3rd graders, and I'm sure there are some faculty who would agree).