Much like today, the United States was deep in an economic downturn. Oil prices were high; smaller, more fuel-efficient cars began replacing the giant, hulking, gas-guzzling behemoths of past decades; and most people suffered from the effects of recessionary inflation. Hence, entertainment was a premium. Anything cheap or free was considered great entertainment.
Combine all these ingredients together and it makes a wacky stew. Throw in a dash of human nature in the form of morbid curiosity (drive real slow past that accident on the highway) and you have a powder keg souffle of zany goodness.
One man, billed as the world's greatest superhero (because he was real) briefly entertained the masses (or small clusters of yokels at county fairs). His name was...
In reality the Human Fly was Canadian stunt performer Rick Rojatt. Who? Exactly. Almost before the popularity of the Human Fly peaked, he faded into obscurity. For a time he was a popular Marvel Comics' character with his own comic book and crossovers with Spider-Man and Ghost Rider.