If it is decades or centuries off, is it really understudied? LLMs are so far from "AI will be able to do any job a human can more efficiently and fully" that we aren't even in the same galaxy.
I don't see how AGI could be centuries off (at least without some major disruption to global society). If computers that can talk, write essays, solve math problems, and code are not a warning sign that we should be ready, then what is?