Ahh then the move to make a console exclusive like this seems very bizarre to me. I mean, I could understand console exclusive to the PS3 or 3DS with much larger, active markets but the PS4 only seems odd to me.
I imagine userbase decay scared them away from making D5 on PS3. While budgets would obviously be smaller (and a port to Vita realistic), sales might be significantly reduced. Disgaea D2 sold worse than any other Disgaea on PS3 (though that's not a surprise) and Guided Fate 2 flopped:
PS3 : Disgaea 3: Absence of Justice ( Nippon Ichi Software ) { 2008-01-31 } - 56,441 / 93,227
PS3 : Disgaea 3: Append Disc - Raspberyl-hen Hajime Mashita ( Nippon Ichi Software ) { 2009-09-17 } - 4,600 / 17,432
PS3 : Disgaea 3: Absence of Justice [PlayStation 3 the Best] ( Nippon Ichi Software ) { 2009-01-15 } - 1,100 / 17,545
PS3 : Disgaea 4: A Promise Unforgotten ( Nippon Ichi Software ) { 2011-02-24 } - 77,449 / 129,031
PS3 : Disgaea 4: A Promise Unforgotten - Fuka & Desco Hen Hajimemashita ( Nippon Ichi Software ) { 2011-10-27 } - 18,610 / 41,686
PS3 : Disgaea D2: A Brighter Darkness ( Nippon Ichi Software ) { 2013-03-20 } - 53,814 / 75,734
PS3 : The Guided Fate Paradox ( Nippon Ichi Software ) { 2013-01-24 } - 24,903 / 40,054
PS3 : The Awakened Fate: Ultimatum ( Nippon Ichi Software ) { 2014-09-25 } - 6,443 / 6,443