For people that have a good experience in college, the piece of paper means very little.
I didn't take college that seriously at first, and I almost flunked out, (but I did barely squeak by after I started doing better my later years).
But like the OP said, college is just as much (if not more) about what you learn outside the classroom. It's about shaping your mind to critically evaluate things, learning social skills, learning teamwork, teaching yourself how to function independently, etc.
I have no doubt of the fact that I would be gainfully employed even if I had flunked out given the magnitude to which those other learning experiences have impacted my life for the positive.