thismeintiel on 26 June 2017
Sony predicts 78M by March 2018. I think they are just using a number they 100% know they can achieve, hence them already using 78M in their PR. I think that's low balling it, and a $199 Slim and $349 Pro will help push it to 80M. But, for now, I'll go with 78M.
Next year, we'll have a full year of a $199 Slim and later a $299 Pro, possibly a Pro Slim. I think that'll help them hit 96M by March 2019. I fully expect PS5 in 2019, but the PS4 should still be able to pull off 110M by March 2020. 120M by March 2021. I think from here the PS4 is basically done and may sell 125M in the end.
