I've noticed that, through past Zelda games, Technology and Industrialization have greatly decreased through the Zelda time periods. An example being as to why the Bokoblins in the past of Skyward Sword had electric weapons and some type of Armour, but when in the future, Bokoblins are dumb, and have wooden Clubs, maybe suggesting that the Bokoblins are smart enough to make their own weapons, but not much more than that. That's the De-evolution, as for the Evolution, take Spirit Tracks for an example. The people are now smart enough to build trains and the such, and yet in previous games (not Phantom Hourglass) Electricity was practically unheard of. Theres lots of other things, but i'm to lazy to list them all.
That's my 2 Ruppee's, anyway.