Because it's a worse game than DMC4 and got bad rep because the devs acted like idiots toward fans of the series as well as the old games from the franchise.
The game is actually not as terrible as could have been but that bad PR disaster that started from the first reveal to post-launch after the game had flopped when they said old Dante belongs in Brokeback Mountain during GDC.
The game may have won over even the more bitter fans that hated the redesign, but because they were arrogant little shits, now they're stuck doing iOS games. I hope DMC4:SE comes out and sells at least 5 times what this did.
Here's an image from that dreadful GDC.








