It'd be interesting to see a study on low E coatings, the argon and other exotic fillings, and of course, ye olde "close the curtain" (which I acknowledge heats up inside the dwelling but still can reflect some) versus awnings. I wouldn't be terribly surprised that the answer comes out either that modern approaches are competitive or even superior overall (especially with the "close the curtain" backup)... but of course, a building has to actually have them before they can help, and that would still leave a decades-large temporal hole between "awnings became unpopular" and "awnings are no longer terribly useful" that can still be explored.