To make it less abstract than the argument that it costs "delta v": it's a bit like asking, what if this rock I placed on the floor impacts a nuclear plant one

To make it less abstract than the argument that it costs "delta v": it's a bit like asking, what if this rock I placed on the floor impacts a nuclear plant one day? It requires energy to move there. This change in velocity, making something drop from orbit by itself, happens across months~years for only the lowest orbits around the earth, caused by stray particles from our atmosphere impacting the spacecraft/satellites there, but at L2 that's afaik not a factor