From 1998 to 2014, annual compensation costs per active-duty service member increased by 76 percent, to $123,000, while the overall defense budget increased by 42 percent — yet, since 2010, the base Defense Department budget, not including spending on the wars in Iraq and Afghanistan, has been declining, according to the Center for Strategic and Budgetary Assessments. So far, the military has dealt with the sharp increase in personnel costs by cutting the number of service members, and has managed to keep expensive weapons acquisition and technology at the same percentage of the overall budget — around 30 percent — as personnel and maintenance and training.

But with the Army, the largest branch in the military, now headed to its lowest personnel numbers since before the World War II buildup, Defense Department officials, particularly in the Army, warn that more cuts could bring increased risks to deployed service members. While the Air Force and Navy, with historic reliance on technology, are widely viewed as more willing to make personnel cuts than their Marine and Army counterparts, even officials in those services say there is a limit to how much more they are willing to reduce personnel.

But a potential gap between good intentions and spending reality remains, and it is unclear how serious the Air Force is about its call to move away from its focus on big, expensive weaponry, in particular advanced fighters and bombers. After all, the report is a long-range forecast that looks to change the culture of weapons development two decades or more down the road, so expensive weapons already in the pipeline remain relatively safe.

Over past decades, similar talk of streamlining the military has crashed into opposition from members of Congress, defense contractors and the military itself, which often work to protect bases, weapons systems and other budget pets. And calls for saving money by adopting new technologies are not new; Donald H. Rumsfeld, a former defense secretary, announced a goal of imposing “transformation” on the military to create a smaller, lighter, more agile — and cheaper — force, but his ideas were forced aside by the terrorist attacks of Sept. 11, 2001, and the wars in Afghanistan and Iraq.

For example, nowhere in the report is there mention of scaling back on the trouble-plagued F-35 jet fighter — in development for 14 years so far — which was temporarily grounded last month after another in a series of problems. Nor is there talk of getting rid the next generation long-range bomber, which the Air Force is working on for around $550 million per plane and which is expected to debut somewhere around the mid-2020s.