School gives you three things: Exposure to a range of scenarios, a safe place to screw up, and someone who knows what they're doing to show you the right way to do it. Like everything else in life, though, you get out what you put in - you can't just show up for four years and magically expect to know what you're doing. There's still a whole hell of a lot to be gained if you do more than just the rote assignments, though, and I'd wager four years spent actively learning at a university yields better than four years studying by yourself for equal levels of commitment.