Matt Grandstaff, Global Community Lead for Bethesda explained on NeoGAF why Fallout 4 will not be coming to PlayStation 3 and Xbox 360.
Grandstaff explained the reasoning simply as,
It is not coming to 360 and PS3, the stuff we’re doing will never work there.
This means players can expect bigger action, better graphics and a bunch of other cool stuff all thanks in part to modern technology.
While there is no official release date for the game, the Bethesda Store did leak that the game will release for PlayStation 4 and Xbox One later this year.