Well if humans can do economically valuable mental work the AI can't then its not AGI, don't you think? An AGI could learn that new job too and replace the human, so as long as we still have economically valuable mental work that only humans can do then we haven't reached AGI.
This is a strange binary I don't understand. There are humans that can't do the work of some humans. Intelligence is, clearly, a spectrum. I don't see why a general intelligence would need to have capabilities far beyond a human, when just replacing somewhat lacking humans could upend large portions of the economy. Again, "it's not AGI" arguments will eventually require that some humans aren't considered intelligent, which is the point in time that we'll all be able to agree "ok, this is AGI".