I'd say some designs will likely become more affordable in the next 2 years. The catch is that there's constantly new design ideas or fab processes still coming out in the SSD ecosystem so it's difficult to say what kind of 4TB SSD, or similar size, will be affordable. I remember with platters we saw some similar advances in the late 90's & early 2000's with 40 wire, 80 wire, DMA, SATA, multiple platters, etc. Other than size and accompanying buffers, or hybrids, not much else has changed in the last 10 years for platters and that's when we finally started to see some major price drops for huge capacities. It's difficult to say how long for a similar trend for SSD's but I'd guess we're about halfway there.