This is a very insightful question. The Progressive reforms passed maintained the Status Quo because they did not fundamentally change who held power.
The Progressive reforms were significant for the time period. They were examples of government assisting those who lacked economic power. They were aimed at helping voiceless individuals in a time period where money reigned. However, the Progressive reforms maintained the Status Quo because they did not change who had authority. The ability to do something significant remained in the hands of the wealthy.
Reforms such as the Pure Food and Drug Act and greater safety regulations did not change the fact the immense power of the factory owners. They were able to operate without economic limitation. Reforms did not mandate a collective vision of power. Workers were still incapable of impacting any substantive change. In the case of antitrust legislation, the government was able to break up trusts. However, the economic system that allowed such unfairness still existed. While these reforms sought to make the economic system more equitable, the unfairness of capitalism still existed. Few people were able to generate economic profit while many were still denied it. Government regulation did not create a more collective economic vision. This same type of argument applies to the ability to recall elected officials and other reforms of the system of representative government. In each of these examples, reforms did not change the existing system. The power structure was modified, but not transformed. As a result, Progressive reforms maintained the existing system.