There's this implication that the same number of people required for reform are required for Revolution and that is not necessarily the case. Revolution can include a large majority of people, but if it did, it's more likely that a relatively peaceful revolution would be able to take place. Violent revolution is typically thrust upon people. Not everyone will want to or is equipped to be able to do a revolution. It's not like every American colonist was behind the American revolution. Many were loyalists, many fled, and many did fuck all and watched it happen around them. Some did a little, some did a lot.
All that really required is enough people organized to fight off the people who would fight to keep the current state alive.