The people in this thread completely dismissing even the possibility of the PS4 outselling the 3DS on a pretty much constant basis are ridiculous.
"Bu-bu-but the 3DS was the best selling console last year and the year before." Great and what did it sell? In 2013 about 14.7 million units according to this website (and this is with Pokemon, MH4 and a $129 model among other things). What did the PS3 do in 2011? Oh, about 14.7 million units, looks like that number ain't that impossible to reach after all.
So either you people think the 3DS is going to have serious YOY hardware growth in the coming years after the incredible 2% YOY growth it had in 2013 (arguably its best year software wise) or you think the PS4 is going to have the same sales curve as the PS3 and take about 5 years to get to that height. Both scenarios are not very likely.