Why the NSA is staying out of Apple's fight with the FBI

The article does mention the split between the FBI's public nature of investigations (they have to prosecute) while the NSA does not really care about methods, so long as it returns results.

The interesting part is that the NSA is compelled at all to help. Why would they? Give up their toys and secrets to help another agency go after someone who is already dead seems to put them in peril for little/ no gain. Unless you believe the "dormant cyber pathogen"[1] line holds any water (which it does not).

[1] http://arstechnica.com/tech-policy/2016/03/san-bernardino-da...