Coasting_Ohio said:
"Also, the depression caused a lot of coasters to get demolished, as did WW2, and the Prohibition."
I don't think that Prohibition had too profound of an impact on rollercoasters. Prohibition lasted from 1919 to 1933. In the 1920's the amusement park boomed in a way that was not paralleled until the 1990's. Then there was the stockmarket crash of 1929. That caused many people to not have as much money to spend so many parks went under or tore down their expensive to maintain attractions (i.e. rollercoasters). Then the rationing of WWII made it difficult to travel to amusement parks so even more collapsed. Then there were the freeways. Today the freeways keep the parks alive, but when they first debuted they allowed people to flee to California or Florida for vacations and the local amusement park suffered. In 1929, Cedar Point had four rollercoasters. In 1950, Cedar Point had no rollercoasters, and didn't get a new rollercoaster until the Blue Streak was built. It was the opening of Disneyland that a park doesn't need thrill rides to be successful. Other parks followed suit by providing pay one price admission and theme areas, usually a western town.
So there we have another history lesson.