But are you sure we know ALL of Satoshi's addresses?
If Satoshi was still mining in 2011 like any other 500+ people mining at that time, how would we know?
A total of 2,650,000 coins were mined in 2011. So Satoshi might be having around 5,300 coins from 2011 (considering the median scenario). It will represent just a small fraction of the coins which he mined during 2009, and so we can ignore them. But proof seems to indicate that he gave up mining in 2009 itself.