What it's not obvious it the amount of technical and cultural advancements Sumerians did. We don't know enough about them as their history has been mostly lost and only crumbles and leftovers can be recovered from the dust of the millennia. Besides a bunch of words still in use, in some form, in modern languages, the writing itself seems not to be the greatest invention, while bringing humanity from prehistory silence to history chatter.

I wouldn't be surprised if we found evidence of more technical and social advancements we have given for granted in the past thousand years.