It cannot push wages below subsistence for essential workers: those involved in maintenance of infrastructure, logistics, national and local security, and secondary health care. In fact for any work in the world of atoms. There are many, many problems to be solved in robotics besides that of common sense. So, workers in those areas will be needed for many decades to come. Wages will be set at a level that keeps them alive and reproducing.
AGI would be able to replace those workers, at which point they aren't essential anymore.