"OK, I hear what you're saying about flash, and mostly agree, but s/flash/solid state storage, and the picture changes somewhat - I just don't believe that spinning rust is going to stick around much longer."
I think that HDD is likely to get killed at the same time as Flash, tbh; when we get a storage solution that is as quick as RAM. That will require a big change in software architecture that will largely obsolete existing drive and memory tech altogether. It's a cataclysm model rather than a gradual change.