Gama's claiming that American PlayStation revenues dropped around $1.3 billion last year, with gains from an expanding PS3 business swallowed by a contracting PS2.
PlayStation family revenue dropped from $6.4 billion in 2008 to $5.1 billion last year, the site's estimated.
Sony's overall US market share has also fallen, down from 30 percent in 2008 to 26 percent in the following year.
Assuming estimates from Wedbush Morgan analyst Michael Pachter are correct, PlayStation 2 software revenues dropped by around $700 million in 2009 compared to 2008.
PS2 hardware received a price cut in 2009, which could have contributed another $150 million in lost revenue.
Another $225 million or more have come from the annual loss of 1.3 million PSP system sales.
According to Creutz of Cowen & Company, the handheld software segment shed $200 million in annual revenue from 2008 to 2009, and Gama estimates at least half of that loss can be attributed to declining PSP software sales.