Aside from the obvious wrong conclusions – like prices cannot fall below . . %, and the analysis is too weighted to the bubble states, there may be a grain of truth to the article.
It may be true that in small Kansas, Montanta, etc. areas the fall in price may be very small. Clearly the big bubble states like Ca, Fl, Nv all have a long way to fall, but a $75k 2000 sq ft house in rural Kansas is pretty close to its economic cost and may retain a greater percentage of its value.
But so what. The economic engine that drove the economy for the last 8 years is Finance, Insurance, and Real Estate (FIRE) and this activity was centered in the bubble areas. The decline in the bubble areas will drag the whole economy with it.