This is theoretically around the corner; Intel and Micron created a memory technology called 3D XPoint that is persistent and is supposed to have latency close to that of DRAM.

Intel just started shipping DIMM modules, though apparently CPU support still hasn't arrived yet: https://www.anandtech.com/show/12828/intel-launches-optane-d... https://www.theregister.co.uk/2018/08/10/optane_dimm_ceremon...