It's almost easier to ask the inverse, what modern "crowd movement" has had lasting effects at all? I'm thinking of big ones like Occupy, or Remain, or the Women's Marches, or Extinction Rebellion for really recent. What actual, tangible change did they directly effect? What concrete legislation? The US civil rights movement actually ultimately resulted in the enormous Civil Rights Act of 1964. Various movements created a full umbrella group, the Leadership Conference on Civil and Human Rights, to coordinate lobbying efforts and help translate public will into Congressional action. And it was needed, because passage was fought vigorously all the way to the end, with heavy filibustering, rule maneuvering, etc. It passed not through some grand awakening but through sustained, multi-faceted application of power, including skillful use of grubby politics by supporters. And of course even it's passing was still only part of a process, there was resistance to implementation, lawsuits, and on and on. Yet none of that diminished the accomplishment or the lasting effect it's had on society.
I'm definitely worried there is an increasing movement towards flashy, feel-good and "exciting" efforts without the necessary accompanying political party effort needed to actually do the work of translating popular will into concrete power. And as there isn't an unlimited budget of political capital or popular attention there really is something of a zero-sum aspect to all this, if people are spending their time and resources on ineffective measures that's quite harmful. We need full carbon cost internalization for example, which will not just dramatically aid in finding the most efficient ways to go carbon neutral but also be helpful in the critical next step of going carbon negative. Protests are likely a necessary component of getting carbon cost internalization laws passed, but we do in fact need those laws passed so while necessary they're not sufficient.
I was trying to say more or less the same, but maybe a bit too terse. [edit: with the qualification that I believe that protests and civil disobedience are essential means in "changing politicians/parties"]
What I was trying to say is that passive voting for the currently available options is not enough. People need to get off their couches and get actively involved in a climate movement and shift the overton window.
> Conversely, consider all sorts of modern disorganized protests, no matter the size.
Which ones do you have in mind specifically?