If no one cares, you really have to wonder why they decided to do it then.But, this whole goblin thing really does sort of line up with what I said before.
Does anyone actually care about the origins of monsters? I mean, sure, you might like to read about it or whatnot, but, does anyone actually care? Are goblins suddenly not usable in Lost Mines of Phandelver because now they have a Fae origin? Does anyone have to rewrite the module in any way, shape or form? Would I suddenly need to rewrite Caves of Chaos because goblins are, many, many generations ago, descended from Fae?
This is my point about tempest in a teacup. Frankly, who cares? It's not going to make the slightest difference in anyone's game. You can run exactly the same modules, in exactly the same way before and after. It's just a nifty bit of flavor text that might lead to more stuff down the line. I imagine that if they release new modules featuring goblins, they might play up the Fae aspect. But, again, there's a million different ways to do that.
It's really funny to me. Paizo completely rewrites goblins and gets nothing but a huge pat on the back for it. WotC does far, far less to change goblins and they are abandoning fans.