Although I haven't gone through all the source material in detail, and am certainly not qualified to give an opinion, hey, it's the internet: My instinct is th

Although I haven't gone through all the source material in detail, and am certainly not qualified to give an opinion, hey, it's the internet: My instinct is that surely nearly every violent campaign is preceded by an unsuccessful non-violent one, i.e. the low hanging fruit of change is always picked by the non-violent movement before people turn to violence. Thus the problems which violent campaigns attempt to solve are by definition more difficult, and success less likely.