I agree—fascism, as I see it, is capitalism in a death spiral. Capitalist economies aren’t able to offer stability or continuous growth. Once things start hitting the upper end of the bell curve, we will see corporations and the managers of capital (politicians) pulling and pressing all the buttons and levers in a frantic effort to maintain course. This won’t work. As a last-ditch effort, fascism is employed by the ruling class as a means to strong-arm against revolution, as workers see wages become incapable of maintaining pace with inflation.
All this is to say: capitalism is deeply flawed. The corporations would prefer a muted underclass over the revolutionary type we can expect in the coming years. And to repress a revolutionary workforce, fascism will be used.
A few points: Capitalism hasn’t freely integrated socialist ideas. Each idea has been won through workers’ struggle. Even after the fact, those wins are clawed back by the capitalist class. They will capitulate as a means to defend against revolution—which flows back into your Zizek quote: capitalism’s way of reinventing itself. But capitalism, as a political philosophy, will always maintain a ruling class and an underclass to exploit.
This is why we must continue to struggle, and why we should not see these small capitulations as proof that socialism will evolve naturally from capitalism.
PS: you would probably enjoy Leon Trotsky’s writings. One book he wrote: Fascism, What is it and How to Fight it. Where he takes a principalled and dialectical approach to the subject.