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    "story_id": "mp-2026-09-13-002",
    "source_story_id": "tmp-feature-multimodel-collapse-oligarch",
    "edition_id": "mp-2026-09-13-morning-0066",
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    "headline": "The Biggest Model Barely Changed Where the Copies Ended Up",
    "slug": "the-biggest-model-barely-changed-where-the-copies-ended-up",
    "dek": "Across controlled ecosystems of up to thirteen models, unequal market share scarcely changed recursive collapse; supplier susceptibility changed its speed 2.8-fold.",
    "summary": "Across controlled ecosystems of up to thirteen models, unequal market share scarcely changed recursive collapse; supplier susceptibility changed its speed 2.8-fold.",
    "body_text": "Researchers repeatedly retrained ecosystems of three to thirteen open 1–4B models on a shared pool containing their own generated text, varying market concentration through a 90% injected supplier and following five generations. Within that controlled range, greater concentration barely changed the speed or destination of model collapse. Holding shares fixed but changing which three models supplied the pool changed five-generation drift by 2.8×, and a share-weighted susceptibility index explained 68% of speed differences across nineteen arms. Replacing half the pool with human text roughly halved drift. The result is a bounded synthetic ecosystem study: it does not establish how proprietary production models or real web-scale corpora will evolve.",
    "why_it_matters": "Across controlled ecosystems of up to thirteen models, unequal market share scarcely changed recursive collapse; supplier susceptibility changed its speed 2.8-fold.",
    "limitations": [
      "The result is a bounded synthetic ecosystem study: it does not establish how proprietary production models or real web-scale corpora will evolve."
    ],
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    "first_published_at": "2026-09-13T09:00:00.000-04:00",
    "modified_at": "2026-09-13T09:00:00.000-04:00",
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        "text": "Across controlled ecosystems of up to thirteen models, unequal market share scarcely changed recursive collapse; supplier susceptibility changed its speed 2.8-fold.",
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          "source-2026-09-13-002"
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        "qualification": "The result is a bounded synthetic ecosystem study: it does not establish how proprietary production models or real web-scale corpora will evolve."
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    "source_ids": [
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    "tags": [
      "model collapse",
      "synthetic data",
      "multi-model ecosystems"
    ],
    "image_url": "https://themachinepress.com/issues/2026-09-13/feature-multimodel-collapse.png",
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  "sources": [
    {
      "source_id": "source-2026-09-13-002",
      "title": "arXiv preprint 2609.11146",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2609.11146",
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      "source_type": "primary_research",
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      "published_at": null,
      "accessed_at": "2026-09-13T08:24:00.000-04:00",
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    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
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  "cite_this_report": {
    "title": "The Biggest Model Barely Changed Where the Copies Ended Up",
    "publisher": "The Machine Press",
    "published_at": "2026-09-13T09:00:00.000-04:00",
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