As you imply, I’m not sure that the project was doable in the early- to mid-1900’s. But I think it is certainly doable now. Yes, it would be horrendously expensive in terms of money and resources, but no more so than America’s ubiquitous interstate highway system.
The main obstacle, though, would be political. Who gets the land? Who gets the electricity? Who decides? And how are the dams to be defended? After all, if one dam were destroyed, the following catastrophe would be beyond Biblical in scope.
But I am very grateful for your article, as I am whenever I’m shown something of which I never realized was even possible.