A lot of the points in the piece are valid. Ofcourse SE would go for this because it will make them more money in some way.
The point about % of users that have both consoles needs a math lesson.
Say 50% of PS4 users had XB1s too...
Right now, that would mean 5M have PS4 only, 5M have both, and 0 have XB1 only. There would be 10M users total. Going XB1 exclusive would lose 50% (5M) users. Lovely.
Say 50% of XB1 users had PS4s too...
Right now, that would mean 7.5M have PS4 only, 2.5M have both, and 2.5M have XB1 only. There would be 12.5M users total. Going XB1 exclusive would lose 60% (7.5M) users.
Say 25% of XB1 users had PS4s too...
Right now, that would mean 8.75M have PS4 only, 1.25M have both, and 3.75M have XB1 only. There would be 13.75M users total. Going XB1 exclusive would lose 64% (8.75M) users.
So, in the unrealistic scenario of all XB1 users having a PS4, they would give up 50% of users. In a more likely scenario, 64% if not more. Losing over 2/3 your user base is not such a big deal according to Polygon I guess.