I mean how exactly does a time line change any of the games?
It doesn't outside of fanservice in games referencing things in the past. It's just something for fans to speculate about between playing the games. Gives people something to discuss you know? I'm pretty sure I read somewhere that there has been an 'official' timeline for a while they just never released any details until now.
I will have to disagree with you on that point. Before there was an "official" timeline, the creators could do any screwy thing they wanted to do; create unrelated games at various and sundry points and let the fans hash out the minutiae of "when" things happen. But now that there is an actual sequence of events in play, a real timeline, the people who make these things are less free, creatively. There's now no easy way, for instance, to create a game that might, for instance, reference stuff from Timeline A in a game that follows Timeline B or C or whatnot.
Yes, some can argue "it's about the gameplay", but I can point out that storyline has played a pretty big role in the Zelda series since at least OOT (maybe even ALLTP).
So what you get is a convoluted mess where adding anything meaningful in terms of storyline becomes close to impossible and you've turned your game's lore into the equivalent of kitty-played yarn. So you end up taking the easy way out- instead of adding onto the mess of tangled fuzz you've made, you just make a prequel and sew it onto the ball. And that's precisely, if you notice, that Nintendo keeps doing- we keep going backwards and backwards.
They did it with Metroid, too, you know. When they made Fusion follow Super, the ending put Samus into a massive, storyline-related pickle, a tangled ball of conspiracy yarn that they STILL haven't added to. So they just kept making more prequels, like the Prime series and then Other M (which was a prequel to Fusion).
Because it's easier!
But the problem of course is that, eventually, you're going to end up with so many prequels that when you finally DO end up trying to continue things, you find that that you've made so much "backstory" that anything new you create won't make a whole lot of sense. Obvious retcons made to satisfy prequels often end up just looking ridiculously silly; MGS4 is a prime example of that. Kojima had made such a fricking garbage mess out of the timeline at that point that he just gave up, pulling plot links forward that made absolutely no sense.
We don't want Zelda to end up with the main antagonist controlled by a sentient talking arm, do we?
Well, I guess it would make more sense in a magic-fantasy world like Zelda than in a world that tries to take itself seriously like Metal Gear.
...
But I digress-
Storyline *is* relevant, and they've written themselves into a pretty big corner with this thing.