It all depends on if adding more layers costs more than making a bigger chip.I'm hyped for post-NAND technologies, but it looks like Samsung has been extremely aggressive with V-NAND. I've heard SanDisk and others say V-NAND is 2-3 years away, but Samsung brought it to the market. Now they are expanding both the number of layers and bits per cell. The large process (40nm?) and vertical over-provisioning can offset the endurance lost by moving to 3 bits per cell.
If Samsung keeps this up, it could drive down stagnant SSD pricing and deliver an existential blow to HDDs, which have also had stagnant pricing. Or at least spur them to be more competitive.