The threats, while very different than the Cold War confrontation, are much more complex, much more varied, and much more disparate and less able to be dealt with by the kind of static and ordered forces that we were used to in the Cold War.
U.S. national security strategy and defense planning recognized that the balance of forces in regions of interest would not remain static and that prospective adversaries would acquire advanced capabilities over time.
Both countries' victories have been eroded in recent years as they have removed their forces from population centers and restricted them to more static positions.