One of the reasons 'City' is notable, is because it is just so big.
The first time I heard about was in a video "Monumentality" [1], which explores why humans throughout history have tried to make monuments; big things, skyscrapers, pyramids etc.
Michael Heizer will die one day, as will we all. But by its nature of being a huge complex made of rocks and dirt, 'City' will continue to stand for thousands of years probably.