(Of ideas and behavior, not blood in the streets!)
Mass teshuvah is nothing if not a revolution.
Rambam Teshuvah 7:5:
כל הנביאים כולן צוו על התשובה ואין ישראל נגאלין אלא בתשובה וכבר הבטיחה תורה שסוף ישראל לעשות תשובה בסוף גלותן ומיד הן נגאלין שנאמר והיה כי יבאו עליך כל הדברים וגו’ ושבת עד ה’ אלהיך ושב ה’ אלהיך וגו’.
Just the other day a friend told me of someone he once knew. The man lives in another city, dresses differently, and traveled a seemingly different path than me in some ways. And it wouldn’t be so simple to contact him. I don’t think he has internet access, either. But he, too, is studying and observing the Torah without blinders, and the results don’t match with modern, mainstream faux-Judaism.
I don’t agree exactly with everything I heard quoted in his name (“There are only two mitzvos Jews still observe as they were given: Lulav and Milah”), but it comes from the same place in the heart.
A handful of truth-seeking individuals is not yet a threat to the establishment, but it’s a start. And it’s genuine “grassroots”; nothing and nobody arranged and organized and led people to the same family of ideas but Divine Providence and independent thinking.
All revolutions start from the fringes; scientific (read Thomas Kuhn), political (read history), and ideological (same, deeply).
(And if you look carefully, even the middle is shifting in many ways, but that part is harder to demonstrate.)
May Hashem lead us all back to Him and the Torah!