I dont' see any point in porting to Lumia or Nexus. Its something about "who gets my money". If you want a modern device, buy the original.

If Nokia sells a Lumia phone or Google a Nexus, they get the money and they don't care, if I use a different OS on it afterwards. For statistics: it counts as success of the respective device, and for money: innovative companies don't get your money for further development of independent "ecosystems".