No, I can't see it selling +20M. This year it sold 1.7M, so let's be very optimistic and say it'll end this year with 5M. Then, to surpass the Wii's sales, the PS3 would need to perform on this level for more 4 years. It's almost impossible.
Bet with Teeqoz for 2 weeks of avatar and sig control that Super Mario Odyssey would ship more than 7m on its first 2 months. The game shipped 9.07m, so I won