Intelligence Failure?

The NY Times has a piece saying that the failure to publicize the death of the North Korean Head of State was somehow an intelligence failure is rather off. As they state:

Asian and American intelligence services have failed before to pick up significant developments in North Korea. Pyongyang built a sprawling plant to enrich uranium that went undetected for about a year and a half until North Korean officials showed it off in late 2010 to an American nuclear scientist. The North also helped build a complete nuclear reactor in Syria without tipping off Western intelligence. 

 Now good intel is not shared. This is so for several reasons and let me list two:

First, by keeping intel secret one sees what the other side says and does. There is great value in that.

Second, by keeping it quiet one protects one's own sources. By revealing it one may reveal a source. That may result in compromising the source.

Simply good intel is never published. It sits quietly and is used accordingly. Perhaps the authors should consider that alternative as well.