I think it was a joke: You know.. from the name: 4DS = 4 -...

I think it was a joke: You know.. from the name: 4DS = 4 - Dollar - Share

I don't think anyone is proposing that as the SP, since it is meant to be sold, and 60c+ has been the historically expected price.

The 60nm scale was a constraint of IMEC's megabit arrays for memory cells, not 4DS's reRam cell. The standalone memory cells have been tested down to 40nm, and I think below, but without the IMEC array fab, obviously.

As the target is SSD type storage the priority requirements were for high balanced read & write speeds, very low die cost and very low operating / power consumption. Die size is less critical, as are other issues such as operating in auto temps and mil spec. These are more important for embedded reRam with its diverse use case but where a higher cost is ok and smaller scale is advantageous.