Anyone know if there is a fundamental limit to how many layers can be stacked? Or is the only limit set by the probability of there not being a fatal defect in one layer, raised to the power of the number of layers? In which case they'll be measured in Terabits sooner rather than later.
(I recall reading in the early days of TFT displays, that defect per unit area considerations meant that nobody could ever make one bigger than 20 inches. We know how that bit of future-gazing turned out, although they do seem to get exponentially more expensive above 55 inches).