"Simply cannot" means that the PS4 will never perform like a GTX980, not that it might be able to catch up. You're misunderstanding.
I also do not read that this guy is referring to the sales at any point, he's only referring to the relative power of the machines?
As I meant to say: Xbone will always be behind the PS4 this generation because it isn't as powerful.
I'm not misunderstanding, I'm reading verbatim (if I were to approve such a tweet). Simply cannot, is not the same as never. One does not simply walk to Mordor