"...But I don’t see how it was extra amazing vs. the grand coullee or hoover dams built almost a century ago...." Count the number of locks and lifts integrate

"...But I don’t see how it was extra amazing vs. the grand coullee or hoover dams built almost a century ago...." Count the number of locks and lifts integrated with them. Count the number of deep water ports built to concert with them. Then you'll START to get an idea of how non-trivial Three Gorges was. It's not just a dam, though a dam even the size of Hoover or Grand Coulee would be non-trivial in themselves for us to do today. (A dam the size of Three Gorges? Not even close to being easy.) Throw in concerting projects, and to call it "not that difficult" is, frankly, laughable.