meaning the Pentagon. Despite chain of command, civilian oversight... at its core the military and supporting industries are a bureaucracy. As such it has a resistance to change and preference to do what has been done before. Overcoming that inertia is a very difficult task. It can be done for a short while, given proper leadership, but once that leader moves to a new position the gains are lost as the system reverts to its previous state.
It is also hard to find visionary leadership. The new leaders are trained by the old and thus have a similar outlook in most cases. In addition, as promotion is based on the reviews of the elder leadership there is strong incentive, career wise, to not rock the boat and follow the majority.
Given the lack of military background of current and foreseeable political leaders, I see no change coming from the civilian side. As above, the system encourages 'last war' thinking and discourages innovation at the strategic level, there is little hope of change from the military side.
Sadly this means the learning curve will be drawn in blood, as has happened in the past.