What is a legacy system? The key is relevance, not age.
Two decades into the 21st century, far too much of the U.S. military consists of systems that were designed and initially produced at the end of the last century, and in many cases back to the late Cold War. While the United States and its allies face growing threats from China and Russia, much of the U.S. military force structure has been worn out by the relentless pace of global operations over the past two decades.
As one example, the size of the U.S. Air Force’s combat aircraft inventory is at an all-time low, while the age of key elements of the combat aircraft fleet is at an all-time high. An urgent need exists to upgrade U.S. military capabilities, that can no longer be addressed solely by modernizing existing platforms. At the same time, the massive price tag associated with the response to COVID-19, along with the pandemic’s lingering impact on the U.S. economy, threatens to blow a hole in any future stability for the defense budget.

