Not gonna happen. xbox 360 in its glory did 84m in 7-8years. In order for the xbox 360 to get there, it ate a lot of marketshare from ps3 in Europe/ROW. Also had Wiimote type peripheral to attract the casuals. This gen, xbox one will be insignificant in Europe/ROW. As you can see, ps4 in killing it in Europe/ROW. Everytime sony gives officlal numbers, they are ahead of what VG chartz is showing. Since there is no Kinect, that mean it will be impossible for xbox one to reach at least 40m. Max 30-35m.
"but xbox one is ahead of xbox 360", yeah I know, it won't be ahead for too long. Xbox 360 first year and a half wasn't good. If people really use this as an excuse that it will reach xbox 360 numbers, they really aren't seeing the big picture.
Edit: I meant 40m in US
