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.

the claim in the OP is "1/3lb burger failed in america

It did, in the 80s, when A&W tried to sell them. I live a 30m drive from the original A&W, they have newspapers up from that time with the people bitching about it. It's a popular "fun fact" style story and has been since it happened

The practice wasnt successful until the early 2000s, a little after it had become a fun fact that became more and more widely known. I think I even remember seeing an ad for Carl's Jr that played on the fact that A&W had failed where they were succeeding and made some joke about dumb older generations or whatever to appeal to the youth

Then they aren't contemporaries of the time when A&W debut their 1/3 burger NOW ARE THEY?!

I'm not really sure what you and the above asshat's motivation is, do you think that somehow your intellectual dishonesty will make people think Americans are less stupid on average?

Frankly I don't even care and I am so fuckdamn tired of your kind.