Phase change memory, resistive RAM... what have they all got in common? That process called 'forming', i.e. zapping the device with a high voltage to create the conductive path, just like a lightning strike. Unless something remarkable has happened since the 1980's when I worked on this stuff, it never was reliable/manufacturable, and never will be.
I would be more than happy to be proven wrong by someone actually selling NVM using this technology, sadly all I see is research papers claiming that it's the 'next generation'.