Wow, you bring up a point I had never considered which is; we've seen this before. In the 1950's and 1960's, you kind-of had to tow the line in what you said, how you dressed, etc... The cancelling wasn't quite as broad as it can be now simply because it wasn't technically feasible back then. You could, however, be in real danger of losing your job if you said you supported a registered Communist's right to speak their mind, for example. Or if you were openly a Communist yourself for that matter.
As you point out, the punk era was in direct opposition of those attitudes. Punks wanted the freedom to express themselves however they wished, as long as it wasn't harming anyone. Want to do make music that is raw and in your face? Go for it. Want to do drugs or even NOT do drugs of any kind? (Straight Edge) You're cool too. Just don't tell me what I need to do or what I can or can't say.
I think you're right that we very well may see a resurgence of that. In fact, I hope we do.