They might pull another 360, which was 4 years after Xbox 1...so late 2017, though that seems highly unlikely.
But in the case that a smaller miracle happens and 10nm is ready by end of 2016 (which both Samsung and TSMC are promising to deliver), and MS is ready to pay for it, then yeah, they might go berserk early with 8xPS4 level console to force Sony's hand.
Still, I think earliest they might try to do this would be 2018.







