This is the kind of deep investigation of a super specific issue I always enjoy reading. This is what I thought the internet would be, 20 years ago.
It's a sign of a "cognitive surplus", because we have more educated people now than we have jobs for them to do. Also it's a sign of how these sites get people to work for them for free, and concentrate huge amounts of other people's work for their own benefit. This poster got nothing for all that work, but SE still gets advertising revenue driven by interest in the content.
What's your basis for this claim? I can see saying "this poster received no financial compensation for all this work" but that's a different claim. It seems to me that the poster must have received somethingp[1], or they would not have put the effort forth in the first place.
[1]: where "something" could be self-satisfaction, ego-boost, intellectual gratification, or any number of other non-financial rewards.