What do you think reality was back then for most people? You think there was equality in other parts of ancient world? It's always a few elite who has the wealth and power. It's still like that to this day, but we have more room to breath.
None of that was passed down, except for a prototype of a religion and language. Now, I dont know why that would be a bad thing, considering your own religion, your text, your architecture, etc, etc, etc. isnt even from Pakistan. And is dominating from North Africa to Central Asia, but is Arabic in origin.
Not that impressive okay, funny considering Pakistan literally doesn't have anything for the last 2000 years except violation from their neighbors.
Art work like that is an example of a complex civilization, yes.