When I was a kid, like many of my friends I would race home after school so I could change and get outside to play. Our time was, for the most part, totally unstructured, unless you consider being told to "be home when the streetlights go on" as structure. There are many theories as to whether exposing our kids to this type of structure and (arguably) overscheduling is good for them.
The trend towards kids having rigorous schedules is a relatively new phenomenon. Perhaps a result of the pervasive guilt that so many of us share because of our need to work longer hours, we've put our kids in as many lessons as possible, some for practical reasons (after-school lessons and sports practice keeps our kids busy until we can leave work and pick them up) and some...well...not so much.