I also think that if Facebook started charging everybody any price (like $10/year, or even $1/year), many people (not all of them obviously) would definitely stop using it, and then the network would be immediately broken because of that, as its value would quickly spiral down since the current value proposition of Facebook as a user is that perceptually basically everyone and their dog is on Facebook.

This question (can Facebook charge people to use its service?) is fundamentally vastly different from the one in the article, which basically is: can someone kill Facebook by buying enough people out of using it?