Well shit, all I can say on the subject is exactly what an originality-challenged dean would say to his class of incoming freshmen (if deans actually addressed classes of incoming freshmen): what you get out of it depends on what you put into it.
Want to take advantage of being able to spend four years learning from some of the best minds in every field of human endeavour? Four years set free on hundreds of possible courses, millions of available books, and hundreds of professors willing to answer (well-posed) questions about their work? It's easy to go into a Bachelor's and come out knowing a lot of great stuff.
On the other hand, if you want to put the minimum of energy into getting your Bachelor's degree by picking the easiest subjects and doing the minimum of work to get through them then, yeah, you can come out of the university without knowing much at all. That's partly the university's fault (they really don't flunk nearly enough students nowadays) but mostly your own.
"But", you say, "couldn't I just spend four years in the library and learn all that stuff anyway for slightly less (once opportunity costs are taken into account) money?" And the answer is: probably not. Books + lectures + professors will teach you much better than books alone. The big enemy when learning from books is not the stuff that you don't know, it's the stuff you think you know that's wrong, because you misunderstood something the first time (it happens to all of us, sometimes books are unclear) and never got corrected on it. (This is why you'll find that the internet is full of self-taught physicists who are disproving relativity or thermodynamics because they've misunderstood some aspect of it).
It's telling that many of the folks who are pushing the "we don't need no education" meme are programmers by trade, since programming is one of the very few skills that you can learn effectively on your own by reading books. Why? Because it's easy to know when you're wrong: it'll result in your code not having the desired effect.