DoD:

During the Cold War, forces prepared to operate in an environment where access to communications could be interrupted ... Through years of practice and exercise, a culture of resilience took root in the military and units were ready and prepared to operate in contested environments. Since the end of the Cold War, however, a younger generation has grown increasingly more accustomed to an environment of connectivity. In the face of an escalating cyber threat, the lessons of the previous generations must now be passed down.

Robert Spalding III and Adam Lowther:

[In the nuclear MAD era,] for every two dollars of defense, the enemy only had to spend one dollar on offense to defeat it. If we wanted to protect 90 percent of the American population it became an astronomical 6:1 ratio.

Gideon Rachman:

The days in which the US alone accounted for almost half of the world's military spending are long gone; by 2014, the Pentagon accounted for "just" 38 per cent.

The Economist:

The real cost of each active-duty service member has jumped by 76% in the past 16 years. If they were to continue to rise unchecked, personnel costs would swallow the entire defence budget by 2039.