His later work on functional programming was more or less a failure even by his own words: Backus: But it was ultimately unsuccessful because it couldn’t take

His later work on functional programming was more or less a failure even by his own words: Backus: But it was ultimately unsuccessful because it couldn’t take in all the peripheral stuff that you had. Booch: Your functional programming work was unsuccessful. Backus: Yes. But also the video adds more colour he's got a dry sarcastic personality.