Quoting from the text that accompanies the picture where he is speaking of the Wall of Death, a motorcycle and car racing venue inside a bowl with vertical walls (you've seen them at the county fair):

"However that, too, bored the masses, still coming down off the carnage-high of auto polo, so Wall of Death owners did what any good entertainer would do: They threw in hot dames and bigger cats. Well, as hot a dame as they could find who was willing to risk flipping a go-kart on top of a furious lion. The pool was ... surprisingly narrow.

Our forefathers were so jaded by the rampant, unchained awesomeness of day-to-day life that they looked at motorcycles defying gravity with zero safety measures and stifled a yawn. Then they politely requested that the show owners mix some comely lasses and apex predators into the Bowl of Death to really earn that nickel admission fee."