Keeping the PS2 alive for so long was a very good plan by sony.
People in developing countries really can't afford to buy this gens consoles but keeping the cheap PS2 on the market gives them a chance to get hold of a still pretty decent console.
Weekly, according to VGC, considerably more consoles are being sold in the EU than the US - unless EU include others - so to sate that the US will be no.1 through to 2013 is a bit puzzling - unless they are talking about individual countries.