The bureaucracy can fight but it can also lose. Blockbuster Video is no longer a thing that exists because of market pressure. Standard Oil was broken up because of political pressure. There have existed countries that, following the conclusion of a major war, actually disbanded the majority of their military forces, both voluntarily and due to external force. Countries have revolutions where the revolutionaries win and then exile or execute the previous ruling bureaucrats.

In theory the same thing can happen through the democratic process, although this is obviously less common because bureaucracies have a solid understanding of how to subvert electoral opposition.