Not every weapon system has a direct and obvious replacement when it becomes obsolete - the nature of the combat itself changes around what's viable given the tech.
Agreed. I meant the role of tanks cannot be fulfilled by drones, and therefore they cannot be a replacement. The tech is irrelevant, the role is relevant.
Even an evolution of the tank's role, because all roles change, will not be fulfilled by drones.
That said, drones cannot replace tanks. Maybe something else will, but drones cannot make breakthrough advances, nor accompany and shield advancing infantry. Drones may be cheap tank killers, but I don't think they can replace tanks.