The dilemma of Defense in Depth

Defense in depth strategy has proven it's effectiveness in preventing cyber threats over the years. At the abstract level, most security controls are designed with two main components; 1) a knowledge base, and 2) a matching engine. Each security product has its own version of a growing knowledge base of feeds (whatever these feeds are). The content and how frequent these knowledge bases get updated are often the basis of competition between vendors. In this context, where these knowledge bases are complementary, defense in depth is meaningful.