If all we ever did was circulate ideas about having a union, not a whole lot would happen. This is a basic point, but an important distinction. There's a difference between doing our jobs well and fighting for social change. Radical politics and everyday writing or teaching may share the common goal of disseminating ideas, but are significantly different projects. But we have to remember, as C. Wright Mills said, that America is a conservative country without a conservative ideology.
Conservatives walk around using the liberal language of empowerment.
The same critique of national ideology works for capitalism as well - it can afford to build up quite a wardrobe of radical clothing. It still walks the same walk. Film theory or Marxism or Feminism in the newspapers is not a sign of radical change. It is a sign of the flexibility and ingenuity of capitalism. Academic publishers especially friendly to academic leftists like Routledge and Verso are still profit ventures, and not simply instruments waiting to be taken up by an insurgency.