2010 at the very earliest. And Sony will keep trying to push it in Africa, South America, eastern Russia, etc, long after next-gen has a stranglehold on the major markets, so it may last into 2012 even.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.