There are many, many examples of change that has occurred on the back of peaceful protest, incidental or otherwise - the Montgomery Bus being one notable example.
The Montgomery Bus boycott was a great example of denying capital to the very same regime that oppressed you in the first place (which i've briefly mentioned in here). However the actual boycott was limited to Montgomery primarily, it wasn't a large scale demonstration and even after the bill passed to remove segregation on buses, segregation still existed at the bus stops, plus some of those who participated in the boycott were arrested too. Also it's important to note that it was the MIA group filing a lawsuit which led to the laws changing - there's nothing to suggest that had the protest gone on, without a lawsuit that any change in laws would've occurred.
As far as non-violence goes, in the immediate aftermath of the bill passing in the Supreme Court - Black Americans who sat in the front of buses were attacked, snipers used to shoot through the windows & MLK's house was bombed, plus many other instances.
Sure, the bill passed through non-violence & it was a great first step in Civil Rights, but the Bus Boycott by itself wasn't the large scale societal change that i'm referring to here, it was simply igniting the match, because the Civil Rights movement lasted 10 years after the fact - again, an incredible amount of violence here.
I'd even argue that segregation isn't completely over when you look at Residential Segregation & School segregation.
I'd also argue that a lot of the success of the Bus Boycott was due to a lack of visibility to those who weren't impacted; word of mouth & passing of leaflets to other black people were the main methods used to drive communication & action in the black community - in a majority black town.
If you were white, it didn't impact you & if you lived in a different state, chances are you didn't hear about it, or couldn't participate in it.
It was a smaller scale demonstration that led to a nationwide change of 1 specific law, but the entire aim was an end to all segregation and that was just the first step.
What other examples do you have?