If somebody does build a true AGI that can replace most human labor at most tasks, I think that there will be just a lot fewer jobs to go around but more production in the world. The question then becomes a political one, which is what happens to the surplus, the abundance that is created by this technology? OpenAI has pledged to put everything above 100x returns on its investments into the nonprofit which then can do what it wishes with it and they claim they'll share it with the world and we just have to take their word for it because there's no mechanism to ensure that happens.