Then Xbox One won't drop below 90k.which is about half of ps4s lowest. But considering the drouht that's coming come September Xbox should b able to do 200k.november 600k. I think ps4 will do 300k and 650 k in the same time.
Ltd predictions by the time 9th Gen comes out
Ps4:110million
Xbox one :75 million( was 65)
Wii u: 20 milliion