Comment by rbanffy

They are still cheaper than flash for cold data, but that’s not going to hold for long. Flash is so much denser the acquisition cost difference for a multi-petabyte store becomes small next to the datacenter space and power needed by HDDs. HDDs require research for increasing density while flash can rely on silicon manufacturing advances for that - not that it doesn’t require specific research, but being able to apply the IP across a vast space makes better economical sense.