Lastgengamer on 26 September 2015
I remember reading somewhere that the reason the PS4 at least does full installs is because developers wanted to have the same guaranteed performance on both disk and download games. I still wish they could've been compressed more to PS3 game sizes, but that probably has something to do with anti piracy measures.
Here is the link where Mark Cerny explains: http://ps4daily.com/2013/11/how-the-mandatory-game-install-on-playstation-4-works/
