XB1 replacement will likely be pushing for 2018. Sony will probably be 2019, to follow on the success of the PS4.
Made a bet with LipeJJ and HylianYoshi that the XB1 will reach 30 million before Wii U reaches 15 million. Loser has to get avatar picked by winner for 6 months (or if I lose, either 6 months avatar control for both Lipe and Hylian, or my patrick avatar comes back forever).