You describe Alain Badiou’s philosophy as revolving around three key questions: i) How does genuine novelty enter the world? ii) How is it distinct from mundane change? iii) And how can it be made to endure? And yet capitalism has become so hegemonic in recent years that it has become pretty difficult to even imagine an alternative to it.
I think the problem you describe, of the commodification of the political imaginary by capitalism, is a very serious one, especially given that this extends to images of resistance to capitalism as well (I refer to this in Badiou in Jamaica a few times as 'rebel chic'). Zizek's reading of the epidemic of apocalyptic Hollywood disaster movies is relevant here. He suggests that capitalism's hold on the collective imaginary is such that it is now far easier, particularly in the face of mounting evidence of environmental catastrophe, to picture the whole planet going up in flames, than it is to conceive of the end of capitalism. So it's a serious problem. I also think that part of addressing this problem does indeed have to take place on the level of the political imaginary itself. For all its many problems, at least the motto of the World Social Forum that 'Another World is Possible' acknowledges the need for an imaginative space in which alternatives to capitalism can be elaborated. But it certainly can't be addressed only at that level, since enormous amounts of energy can be wasted on building utopian visions, when significant change, at least from a Marxist perspective, never comes only from ideas.
