the idea that they got rolled completely makes anarchism entirely unconvincing
Some interesting points in the rest of your post but this one feels really weak. This is the same stuff proponents of capitalism spout. The USSR got rolled so therefore communism is unconvincing, etc.
I find the disconnect in logic here suspect when it comes to one ideology vs another. When communism fails in an instance it "justifies investigation", when anarchism fails it means anarchism is "entirely ineffective".