About a year ago, I posted a brief discussion of security strength through diversification, using the U.S. Air Force's fixation on fifth generation aircraft as an illustration. A great counter-example is the U.S. Navy and what Wired.com refers to as the Navy's Stealth Plan B.
For those who are unaware, the Navy hasn't so much diversified its fleet of aircraft. Instead, the Navy has achieved some economies of scale through a pretty intelligent approach. When the venerable F-14 Tomcat was retired in 2006, it was replaced by the F/A-18E/F Super Hornet. Meanwhile, the Navy is replacing its EA-6B Prowler electronic warfare fleet (itself a derivative of the A-6 Intruder) with the E/A-18G Growler. The Super Hornet and the Growler are derived from the F/A-18(A/B/C/D) Hornet. This has allowed the Navy to manage some of the risks of maintaining multiple supply and production lines, resulting in economies of scale. The Navy has accepted some parallel risk by placing most of its aviation eggs in one basket, so to speak.
Obviously, these concepts are applied on a very large scale, but the concept can be applied on smaller scales as well.
