In my understanding, the following factors are currently in play. * CPUs are a whole issue on their own and the reasons for slow progress are well known. * GP

In my understanding, the following factors are currently in play. * CPUs are a whole issue on their own and the reasons for slow progress are well known. * GPUs have been improving a fair amount, I think, but prices are very high now due to cryptocurrencies, and much of the improvement comes from the large amount of flash memory... * ...SSDs and RAM (flash memory) is staying expensive due to extremely high and growing demand. I have also heard suggestions of collusion among RAM manufacturers, but I don't know. Think about how much new RAM and disk space is added to servers for YouTube and Facebook alone each day. Furthermore, flash memory is in high demand for almost all other computational systems, particularly, phones. * HDDs seem to have, to some extent, hit a limit on how well the technology can perform, and demand for storage is very high (see above). Perhaps manufacturers are reluctant to invest further knowing that SSD technology is catching up?