I know that in college, I definitely came across ideas and subjects that, if it wasn't explained to me, I would probably not have figured it out on my own. That was certainly true in my engineering classes and some of the more advanced math and physics classes.
Three of my math classes were all theory, and every quiz and every test was writing proofs. I absolutely guarantee I could never have learned it without having had it explained to me. Freshman and sophomore physics were made considerably easier with the many demonstrations held in class (it was nicknamed "The Magic Show").
The other classes, most of it I did teach myself. I taught myself Russian, for example, and it's amazing how useful THAT turned out to be. I taught myself International Relations, Nazi Germany and History of Religion in Colonial America, and of the Roman Republic. How? Because it was all reading. All of it. The tests were all essays, all of them.
Some of it was ALL taught. I was in Navy ROTC, and almost everything Navy is NOT intuitive - someone tells you what it is and you assimilate it.
I had a discussion with a roommate about this, once, in college - aargh! - 30 years ago. We agreed that an enormous amount you teach yourself, through assignments and homework and reading. So we asked ouselves - why in God's name did we pay some institution 8k a year to do what we could do ourselves for free? Besides getting credit for it?
We decided that it was the cost of humiliation. You paid the money to force yourself to learn - the higher the cost, the more was expected, the higher the level of humiliation if you didn't follow through.
Well, we were 19 at the time. To us, the most humiliating thing in life was flunking.