Are youth Sub-cultures Genuine signs of Revolt of Simply the Manifestation of Style?

Sub-cultures can be a revolt. They can show dissatisfaction with the politics in the time of their conception, take for example the miner strikes during Margret Thatcher’s rule as PM. They can embody a new trend or movement in music, as we have been seeing recently with Emo. They can be formed around a minority community coming together for security like the black ghettos of 60’s America. On the other hand subcultures develop a style which allows for members of that subculture a free expression of identity through the image of the self whilst also removing and indicators of class or job they develop a uniform. You can be a bank clerk by day and a Goth by night.
However, often these projections of self image and the cultures, communities, grievances or sounds that initially started and formed the core of the subculture become common place. Adopted or marketed to the masses it is no longer a threat so the revolution, the statement, meaning or message dies and it simple becomes a fashion with no meaning.