Look at the growth year to year from PS3 sales. Keep in mind it will continue to grow for another 2-3 years while PS2 decides to die off. The software is really ramping up for PS3 as developers get a solid working engine in their studios and get used to working on the platform. Also keep in mind that as the price drops sales go up dramatically. $249 and eventually $199 price points will be huge sales. I expect this year the PS3 will sell 14 million, then next year 17 million.
On top of all those points above I expect the sales to also surge as 360 starts to show its age and people just get tired of Wii's non-HD capability.
Everyone needs to remember, the console is FAR from its peak record year sales. It's still $299. That's what 360 launched at and STILL $50 more than Wii launched at. A lot of people just can't afford $299 right now (+ another 120 or so for a couple games when you buy it).