I don't see Sony dropping their price at all, because they need to start making money on the hardware.
I think their estimate is unrealistic. The only way I could see them meeting their forecast is if they drop the price by $100 (which would cost them hundreds of millions of dollars), if Move is a big success and Natal / 360 Slim launch is a bust. That's a lot of ifs.
I hope they're not expecting GT5 / LBP2 / Move to increase sales without a price cut?
Personally I see sales staying at 13.0m for next year.
Another take on this would be to look at total consoles sold in a given year. For 2009, we have 47.21m sold. For 2010, we have 43.53m sold. If 360 sales are 10m in 2011 (and I only see this happening if Natal is huge), then we would have 43m sold. I don't find it probably that total sales would not drop this late in the generation.
I am looking forward to E3 to see if they have some huge announcement to prove me wrong.