The problem with Von Neumann probes is they couldn't land on a planet like Earth and use it as a launching off point since the escape velocity is too high for a

The problem with Von Neumann probes is they couldn't land on a planet like Earth and use it as a launching off point since the escape velocity is too high for a simple probe to produce off of whatever it can extract from the soil. If any landed here it would have eroded away by now, and for all we know it could be all around our solar system and we wouldn't know.