First, this research paper is about a game theory analysis about a political situation that may have made the French and Scots leery of being vulnerable to usurpation by arming a large population. The material on pages 691-693 is all background material, not the actual research material of this paper.
I did read 691-693. I am not contradicting any of the information in it; merely saying that I think they are overstating the direct superiority of the longbow. Strategically and tactically, it's clear that arming a large number of archers and using them in the early battle is superior, and the cost and simplicity of the longbow makes that much easier; but it's not because a single longbow is better than a single crossbow. I think that the longbow was a superior weapon, in the sense that the armies that adopted the longbow strategy clearly beat those that relied on crossbows, but I think that the way that the paper couches its introduction makes it sound like, side by side, a longbow was a superior weapon to a crossbow.
I'm not talking about modern crossbows, I'm talking about reproduction medieval crossbows. I do medieval recreation as a hobby, I shoot longbow, I know people who shoot crossbow. The longbow is faster, though as I mention, I know people who can reload and shoot from the hip and get 6 accurate shots off in 30 seconds. And the crossbow is more accurate, gets better range, delivers more power, and is easier to shoot.
Now, I don't shoot a 160 pound warbow, I don't have the strength for it. If I did, I would get some more power and range out of it, at the expense of accuracy and speed, as I would fatigue much more quickly. With a crossbow, you can use both arms and brace against your hip to draw, so even without any stirrup or crank, you can shoot a much heavier crossbow than you could a longbow. That extra power means more penetrating power and a flatter quicker flight (or more range if you increase your angle), and the fact that your muscles are not straining to hold the bow drawn means you can aim more accurately.