I think the reasoning for that timeline is a line from LttP that references a war that happened for the Sages to seal Ganon away. So Link fights Ganon and loses, and then the Sages band together and sacrifice themselves to seal Ganon away in the Sacred Realm, leading to ALttP.
Compare it to the timeline that leads to a Wind Waker, where Link never comes to the future, the Sages never exist, and the goddesses flood Hyrule to stop Ganon. And in the child timeline, that future never even gets a chance to happen since Link stopped Ganondorf.
You guys are thinking about it too linearly; the split timelines are different possibilities of what COULD happen. Link doesn't go around systematical creating offshoot timelines. <_<
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