To blindly assume patterns such as "80/20" hold everywhere would be foolish - rather, it is better to empirically verify them first in each case (as done by the article). Further, I wonder what makes you think the writer is surprised in the least...
You can verify it, but it seems like a smart hypothesis to start with rather than assuming the inverse.
I see 80/20 EVERYWHERE now. It's hard for me to think of things where it isn't applicable. Maybe I'm just going crazy.