To be fair I think we'd be able to claim AGI is here if that problem is solved. At this point the models are so smart they're borderline super intelligent if they were cognizant of hallucinations and their own shortcomings. If GPT 5.5 or Opus 4.8 could tell you "I don't know" they'd certainly be "smarter" than any individual human. Some specialists might be better in niche domains, but I don't know of any humans who are experts at that level in every field.