Parents were definitely not as worried about kids hurting themselves as today's are. Play with whatever you could find, and wherever you could get to.
This was probably filmed in a grim neighbourhood of a city, but even in a picturesque country village, there wasn't a lot of money about in the '60s. I certainly played in farmyards, making dens out of straw bales, and climbing rock faces in quarries. All banned, or at least frowned upon, by the H&S brigade.
Was life cheaper? Were we more tolerant to the idea of tragedy because we had just gone through a war? Were we still accepting that a percentage of children died young and that shit happens?
Or is it the social pressure on parents that if ANYTHING happens to your child, it's your own fault? So now children don't play out.