If a revolution were to happen, a mass audience would already be enacting communism. Otherwise, no. It is not possible for communists to "reach" a mass audience within the confines of capitalism for obvious reasons.
If we have no business with the construction of the future or with organizing it for all time, there can still be no doubt about the task confronting us at present: the ruthless criticism of the existing order, ruthless in that it will shrink neither from its own discoveries, nor from conflict with the powers that be.
- Karl Marx