Post-postmodernism is a modernist label

This is a pretty short and simple argument, but I have a problem with the concept of post-postmodernism, because it basically serves no other conceptual function than to fit postmodernism into a dialectical relationship with modernism: modernism is the thesis, postmodernism the antithesis, and post-postmodernism the synthesis.

But the idea that the singular narrative of philosophical movements in a linear sequence is a modernist construct, and the idea that it would continue to make sense beyond postmodernism, justifying the idea that postmodernism "ends" and some easily nameable construct "begins" misses the point of postmodernism.