However, there's another possible interpretation: AI researchers chose to pursue their field because they believed true artificial intelligence was possible and wanted to pursue it. They steeped themselves in the literature of superintelligence and set that as the target, which primes them to buy into their own field's hype.
This is their life's work: of course they believe in it. We should be careful not to take their expertise in deep learning's foundations as evidence that they have expertise in where it will end—no one can know that yet, and they're the people who chose this path of research because they believed in it before anyone else did.