I don’t try to prove negatives. You go ahead and show us the plethora of great art that compares to those old masters that would be found strewn about the ruins of our cities...
In my experience, they would find a whole lot of canvases filled with abstract shapes and blotches of paint, and maybe the occasional “dogs playing poker”.
Granted, Picasso's art seems to be like that lining the halls of elementary schools while artifacts dug up from the ground have real class.