The "typical poor" American may be. That does not make it either uninformative or--unbelievably!--not worth reading. I know, personally, numerous people who have mentioned either in passing or in detail stories that would not be out of place in what Scalzi (or many of the comments) wrote. Who am I--or who are you--to dismiss them because the teller may be worse off than your declared "typical poor"?
I am fortunate to not be among those with stories like that. So regardless of whether it is the "typical poor American", I suspect that it is quite informative for me, and I would hazard a guess for many others, to read it and remain cognizant of it.