Storage Will Be Much Less Free Than It Used To Be by David Rosenthal. post
For the purpose of building a model of long-term storage economics, the endowment approach is essential; it effectively computes the net present value of the expenditures that data incurs through its history and allows apples to apples comparisons between different technologies.
Slowing of the Kryder rate should not have been a surprise. Here is Randall Munroe's explanation. xkcd. In the real world exponential growth can't go on forever, it is always just the steep part of an S-curve.