Agreed with Axle, but I'll put my two cents in there.
Ganon"dorf", as in the man, like Axel said, was never defeated by Link on the CT until TP. So, in that game, he basically had no real fear of Link or belief that Link could defeat him. In WW, which plays off the AT where Ganondorf was defeated by the Hero of Time, Link is much younger. He's basically just a random kid who doesn't even have the blood of the hero in him (or the blood of the Knights of Hyrule), so of course Ganondorf wasn't worried about him. And that pretty much sums up what we have seen of the man, Ganondorf, so far.
Now as for his beast/pig form, Ganon, like Axle said as well, the creators weren't thinking about past things while making those games or what could have happened before. But there is still a few times that Ganon has been beaten by a similar Link. When we look at ALttP, apparently, that was a point in which Ganon was at his most powerful. He had complete control of the Sacred Realm (which was the Dark World), built his base of operations around where the Triforce was being held, etc. So with all this power, I doubt he was worried about Link or anyone for that matter trying to disrupt his plans. Same kinda goes for FSA. Ganon had found the Trident of Power, so I guess he figures that it would be enough to defeat anyone in his way. LoZ, well, is LoZ. Its very basic, so what can you say?
So in the end, we see that Ganondorf never had to fear Link becase A.) A hero hadn't technically beaten him yet (CT), and B.) Link was just a random kid in WW. With Ganon (pig), we see a pattern of him gaining more/different powers that he believed would make him invisible. Its not so much like Bowser, where each time he does the same thing (kidnap Princess Peach and sets in his castle), although he did have varying forms of combating Mario. Bowser never really had any extra power in himself, while Ganon has always searched for additional power before taking on each task he sets out for. LoZ was much more like the Mario/Bowser scenario, so you can't say a lot there.