It depends on what happens this year. We could see the gap closer quicker, stay relatively stable by the end of Q4, or widen from this point all due to whatever changes which are made in terms of hardware, software, peripherals do to the balance of things.
The only way that the PS3 will cross that mark in 2011 is if both the gap at the end of 2010 is smaller than present and closing. However predicting that far ahead is folly because we have Arc, Natal, likely Xbox 360 slim/price cuts and the ever present possibility of megaton software releases coming exclusive for either platform of whose impact we cannot anticipate at present.
Do you know what its like to live on the far side of Uranus?