Well, it's not very nice to talk about people spending decades on failure, but I guess I can give some examples.
Cycorp still exists, from 1984. However, D. Lenat's approach to AI by ontology engineering has basically been completely infertile after about the early 90's.
Feigenbaum's expert systems stuff was a basic bust, it led to the Japanese just throwing that stuff away. People spent an incredible amount of effort and time systematizing expert knowledge and making expert systems and it was not a happy time. Much of that knowledge went into probabilistic forms, culminating in the Bayes net. The most famous application of Bayes net: Clippy (there are a lot more successful applications, but still...)
It was believed shortly after the AI conference that computer vision could be solved by a summer project in the 50's. That didn't happen.
Cycorp still exists, from 1984. However, D. Lenat's approach to AI by ontology engineering has basically been completely infertile after about the early 90's.
Feigenbaum's expert systems stuff was a basic bust, it led to the Japanese just throwing that stuff away. People spent an incredible amount of effort and time systematizing expert knowledge and making expert systems and it was not a happy time. Much of that knowledge went into probabilistic forms, culminating in the Bayes net. The most famous application of Bayes net: Clippy (there are a lot more successful applications, but still...)
It was believed shortly after the AI conference that computer vision could be solved by a summer project in the 50's. That didn't happen.