I mean, no? The USSR had a successful revolution and was almost defeated by the white army. The Paris commune was crushed by the forces of capital, Salvador Allende was murdered by capital, Cuba barely survived its infancy or the fall of the Soviet Union, COINTELPRO has crushed many nascent movements as well as the BPP, the government of Iran was couped as well as many others.
Pretending line capital does not have immense power is silly. Pretending we do not exist in a society wherein left movements are routinely hinted, crushed, suppressed, destroyed or subverted is naive and silly.
Every single revolution was long and drawn out, the victories precarious and hard-won. It's not a cake-walk. And even then it is impressively idealistic to go "the people united are indivisible" because yeah sure, but that unity has never been available. Reactionaries are a thing, fifth columnists are a thing. The Bolsheviks and Mensheviks fought each other, the makhnovosts and soviets fought each other, China and Vietnam waged war against each other.
You gotta accept the reality of the world you're in, and work from there. I would suggest reading Engels "On Authority"