Ideological groups have end points. They don't usually achieve them, as it takes time. Pragmatism/instinct tends to neuter movements when they become liabilities. However, a feature of modernity is distillation. Instability leads many to reason their failure as a lack of purity.
But pragmatism is a weak force for millenarians in a modern world. The moment the cracks become visible people begin to worry. The left looks pretty unhinged right now. They're acting kind of weird right? They're not dying however, they're purifying.