Tuesday 2nd June 2015: 12.17am.
Every year I update my graph comparing hard drive bang for the buck to SSD bang for the buck, adjusted for inflation. There is very little new to report this year actually, hard drives are following their regression curve almost exactly, as are SSDs. The change in curve fit for hard drives +0.000113 and for SSDs -0.000045, so tiny - the future projection for SSDs in 2020 improved relative to hard drives by a small bit, but hard drive capacity growth still outpaces that for SSDs, and we all expect NAND flash density growth to go linear after 3D NAND well before hard drive areal densities run into hard Superparamagnetic limits.
Raw data can be found at
http://www.nedprod.com/studystuff/SSDsVsHardDrives.xlsx