Why does the Zelda series exclusively focus on Ganondorf as an antagonist?

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thekitchensink said:
I want it to seem like it's Ganondorf, but then some awesome new guy comes along that's too powerful for Link or Ganondorf to handle alone so they need to team up.

That sounds WAY to much of a cliche to me. Surprisingly though, if they make it seem new enough, I think it would work.