Can grassroots campaigns happen?

I am in Brooklyn, and witnessed the campaign that Mamdani ran for mayor. I saw people mobilized from the parks to knocking door to door on every building around my neighborhood. They came to my door 3 times over the course of a year, and I'm on the 4th floor. Mid 20-late 30 years olds…

It begs the question, however. Can this occur in Houston, and other car oriented cities; can grassroot campaigns sprout from nowhere? I am genuinely curios around the culture on this.