And that will probably be the end of the road for new HD tech
I've been told that since Seagate closed their advanced research facility and fired all of their bleeding-edge PhDs, all of those physicists have entirely left the field. Nobody else (i.e. WD) had or has an equivalent facility. All improvements you will see in the future of spinning rust will be incremental progress on technologies that have already been discovered, unless someone sees fit to create a new lab, and spend 10 years building the expertise again.
So this is a self-fulfilling prophecy: There will be no more significant advances in HD tech. As a result, SSDs will triumph and HDs will fade away except maybe for archival purposes.