I just don't like to say anything is impossible. I could say 99% likely. I think it is 99% likely that the PS4 will not outsell the PS2.
imo: i hate the word "can?" and should never be used for a prediction.
Of course it can, no one know what kind of madness can happen in the next years, who would have expect Switch to sell 1 million in a non holiday NPD just back in December 2019?
2020 was/is absolutely out of controll. and there is no way to know if in 2021 or 2022 even more crazy things will happen, to the videogame market, to the world in general, or just at Sony.
question should just be "Will PS4 outsell PS2?"