Gandhi's methods have been tested outside of India, perhaps most famously during the civil rights era in the US (if we write off the influence of those who were not wed to nonviolence and noncompliance). In that case they had the benefit of an interested party that consisted of a double-digit percentage of the population (and a far greater percentage in areas with particularly egregious issues.)
The problem with advocating noncompliance and nonviolence is that if you miscalculate the breadth of your support or your oppositions capacity for violence, then not only will you have accomplished nothing but you will have actually damaged your cause by removing yourself from it.
As a radicalized person, there cannot even be futile resistance, because if the violent people were to kill all of their enemies, there wouldn't be any violence left to commit. If so, mission accomplished. It's very much a love thine enemy philosophy.
When I say that Gandhi's methods haven't been tested outside of India, I'm referring to people passively offering up their lives to the state. Did this really happen during the civil rights movement?
Personally I believe that this kind of self-sacrifice is not worth it, even if change is effected.
Nonviolence is not a goal for me. I consider it a tool with limited application. Failing to build a doghouse with a hammer, instead of successfully building the doghouse with a screwdrivers, is nothing to be proud of. The doghouse is what I am interested in, not the application of hammers.
Or to put it in more concrete terms, the world would not be a better place had the French Resistance chosen to adopt nonviolent noncompliance. Their acts of violence were, without any question, justified and "worth it".
And yes, people were absolutely putting their lives at risk during the civil rights era. People were being beaten and in many cases, killed.
It's not about what you build with the hammer that matters to this person. It's that he consistently uses the hammer regardless of what is built or how efficiently it is accomplished, because he believes using the hammer to be the true way of life and far more important than the product being created. By using a more suitable tool he believes that he has already lost.
It's a zen thing.
Had the French Resistance decided that the principles of nonviolence and noncompliance were more important than killing german officers and blowing up trains, then I would think far less of them. If he thinks that they lost the moment they used violence and sabotage, then I think he is wrong.
Edit: I disagree with Gandhi, not him.
If acting according to your beliefs is selfish... well then aren't we all selfish (arguably true)?
Don't be too hasty to judge.
Whether it would be effective for non-believers (i.e. the people who aren't willing to put their lives on the line) against other regimes is hard to say. I'm not sure it has been tested outside of India or ever will be, since it requires suicidal amounts of willpower to follow through.
So, while not advocating suicide-by-aggressor civil disobedience, I also think it's purely speculation as to what would happen if it were tried on a large scale. Closest thing that comes to mind is the Tiananmen square tank man, and that was one guy.