There are two crash in the history of skateboarding. In 1965, skateboarding's popularity suddenly crashed. Most people assumed that skateboarding was a fad that had died out, like the hula hoop. Skateboard companies folded, and people who wanted to skate had to make their own skateboards again from scratch.
As the '70s closed, skateboarding faced its second crash in popularity. Public skateparks had been built, but with skateboarding being such a dangerous activity, insurance rates got out of control. This, combined with fewer people coming to skateparks, forced many to close.
However, skateboarding coped with everything!
A next big step was the further development of the shape of the boards. Larry Stevenson invented the "kicktail", Frank Nasworthy invented urethane wheels. With the new material it was possible to ride smoother, faster and more comfortable.