Video games also failed in America. Some even thought it would never come back into prominence, and I don't recall if it's related but the writer of the Wticher books sold rights for the game in hard cash and not percentage of profit because he thought they'd never make money as a video game.

Failed and such doesn't mean forever. Things can change or changes in advertising/quality control can restore dead markets. Now maybe this means as you said it wasn't American stupidity, but were also talking Americans who supported segregation at one time and by majority now do not. As different people grow up or even if people heard about this and learned to be less dumb, the conditions in which the original failure could have changed, making the statement true at the time.