> Can someone provide studies or articles demonstrating the effectiveness of large protests in changing the populace's views?
Protests aren't about changing people's views as much as about normalizing active engagement by the silent whose views on the issue (even if they haven't deeply considered them prior to the protest drawing attention) already favor the protesters.
When people already opposed to position a protest takes dismiss it as unconvincing, they are missing the point. Protests are about mobilizing allies not converting enemies.
> I struggle to think of what the Women's March or Occupy Wall Street tangibly accomplished.
OWS directly produced the rapid development of anti-elite populist movements of both the Right and Left which subsequently displaced the dominant faction of the Republican Party and drastically weakened the dominant faction of the Democratic Party, it's a major reason that we have the President we have and that the pool of potential opponents for him in the next election looks like it does.
The meatspace Women's March and the online #MeToo protest movement were the central mobilizing elements in what has been one of the biggest ad most rapid social and political mobilizations of women and around women's issues—in government, workplaces, and society generally—in this country’s history, which had adverse repercussions for a number of very powerful people. It's a key element in the biggest increase in women on Congress from one Congress to the next ever.