This is why this split was so unexpected, something significant must have happened at his death and there should be a good reason as to why.
It did, the Triforce split into separate pieces for the first time chronologically.
I've said pretty much since the timeline was revealed that calling them 'Adult', 'Child' and 'Hero Defeated' may be misleading. Calling them 'Wisdom', 'Courage' and 'Power' would make things clearer, or at least clearer if you were to see it the way I do. I'm not going to say the way I interpret it is correct but this does make the whole Link-Got-Deaded thing plausible at that one specific moment, I feel. The Triforce is supposed to be claimed by someone who has those three qualities in equal balance.
Skyward Sword spent the whole game making sure Link fit the bill perfectly before he was allowed near the thing. This need for balance implies that each piece of the Triforce is as powerful as the others, albeit in their own way. An object of three balanced and equal forces wouldn't make much sense if one of them could trump the other two, right? So when the Triforce splits during
Ocarina of Time and a piece goes to Link, Zelda and Ganondorf I interpret this to be the cause of the timeline split. Each piece of the Triforce has its 'victory': Child Timeline sees the wielder of 'Courage' return to the past and prevent the whole thing from happening; Adult Timeline sees 'Wisdom' as the only piece physically left in Hyrule after Ganon's defeat; Hero Defeated sees 'Power' defeat the Hero and then corrupt the Sacred Realm into a hive of evil.
In this way each individual piece beats the other two, in a manner of speaking, and thus over the whole cosmilogical-quantum-continuum-of-space-and-time-and-wibbly-wobbly-energy-and-dark-matter-or-whatever the Triforce manages to retain its balance since all three pieces were able to triumph. Of course, this is a poor solution as it basically means there will be many more incidents caused by the now split Triforce(s) but then Goddesses be crazy, yo. The 'Hero Defeated', or 'Power', timeline has the Triforce brought back together by Ganon (it had to be him because this was 'his' timeline) and then it goes on to help Hyrule prosper for generations. The other timelines just haven't gotten to their 'unification' point yet.
That's how I make sense of things and in there is our reason for why every death does not create a new timeline. It wasn't Link dying that split the thing in the first place so why would it do so at other points? Call me crazy but this just how I see it. Who knows, maybe I'm so wide of the mark I'm not even talking about Zelda anymore.