The name of the thread is provocative, but the premise is valid - I have yet to see anything produced by multi-agent frameworks (langchain or bespoke works) that produced value. Anthropic pushes vibeCAD, vibeVFX, vibePowerPoint but the results are underwhelming. The real value is in codegeneration and autonomous infra, research.
On my own evals I have seen this, though the improvement may not have been worth the extra cost.