[Jouvence]

HAMR/MAMR have been well understood and just on the road to commercial viability since at least 2014 (probably long before, but that is when I came across them). Toshiba being such a small percentage of the disk market makes their later deployment of this stuff easy to understand simply from the standpoint of having a smaller research budget.

A subsequent technology to expect is the separation of magnetic domains into small islands on a non-magnetic substrate, rather than the current approach of applying the magnetic field to regions of a continuous all-magnetic medium. This would be paired with heating, in what I only remember being described as "heated dot magnetic recording".

That was where the technical roadmap for HDDs ended last time I checked. After that I guess platter additions will carry us to the end of the decade.