Congrats to Sony for their continuing success with PS4. 30+ Million by the end of the year should be easy for PS4.
Even if Until Dawn is not a big hit (being the only exclusive this year, unless they sneak something in at Xmas, last minute) they still have very strong 3rd Party support with games like MGS 5 and Fallout 4 to take them through the holiday with little effort and then they have the build up of Uncharted 4 and Ratchet & Clank to kick off early 2016, so their target of 39 Million by March 2016 should be very achievable too.