Looking at the beatiful show, I cannot avoid thinking: “each of them a potential weapon”.
So in fair weather, when communication is smooth and all navigation systems are working, it’s entirely feasible to coordinate a swarm of 10 000. Wow. :)
Soon enough, they will be coordinating each other in the presence of electronic warfare, and swarms of 100+ fly already, so 1000 is the next step. Anyone doing air defense is probably designing energy weapons (lasers, masers, etc) at a pace approaching madness, besides making ever-cheaper drones.
As for the environmental footprint - if each drone withstands 10 performances, they will probably save resources. :)
Unfortunately I don’t know.
To correlate the effect with social processes, one would have to plot the same graph for multiple countries and see what processes occur in each history at the time of the lines forking apart (assuming they do so).
Some guesses: automation, perhaps globalization of supply chains, something related to the effectiveness of employees at bargaining with employers?