Despite the possibility of differing opinions in this thread, I think the article has not done a good job of explaining the realities of the process, so anyone here who is not familiar with how animal work gets done is coming in with a purist misunderstanding. Everything is reported (in the US), but not in publications.
Looking at publications alone for animal accounting would be like if I looked at the checking accounts for everyone in a country and wondered where all the money went. Of course it's in savings, investments, cash under the bed... but I only looked in one place. I cannot conclude money is unaccounted for when my search was incomplete by design.