Its very possible
1. by the end of fiscal 2010(march 2011) there ll be 42,43 millions and thats 4 years on market(in eu it was launched in 2007)
2. at 199$ we ll see easily 16-20 millions per year, i believe this ll happen in 2011,2012,2013 depending when we see price cut(my guess september 2011)
I know a lot of people with wii,360 or pc who wants ps3 but 300$ is still too much for another platform
by 2013 there ll be about 80 millions at least ps3 out there, new gen ll roll out but for another few years sony ll manage to sell another 20 millions, why not