None of these technologies is yet mature enough to replace flash, but some are close enough that they may be used to augment flash soon. It's important to realize that there doesn't have to be a single winner. Neither SRAM nor DRAM “won;” modern computers use SRAM for caches and DRAM for main memory. Future computers may well use a combination of four or five different memory technologies to provide a more gentle memory hierarchy. There's space between DRAM and flash for at least one more layer.
In the next article, we'll take a look at some of the changes that this kind of system requires from operating system designers.