As far as Skyrim is concerned, it's plausible, since it is a magical world, and it was magic that animated the skeletons and the old dead norse folks.
Magic should not become an excuse for inconsitency or bad writing though just because you need a Deus Ex Machina so badly to solve a problem.
As my friend said to me, "You're right, and I disagree with you."
Yes, you are right. But, magic frequently is used as a get-out-of-jail-free card to do things like that in magical universes, and we're pretty much used to that. It stilll feels pretty cheap in skyrim/oblivion/etc because beth likes to throw in "skeletons with nobody there to animate them and no explanation for hwy they exist" or simlar tricks to "use the IP to generate more things to blow up without explaining". But it doesn't feel quite as cheap there as it does in Fallout because magic.
So, yes. Magic is a cheap Deus Ex Machina. In skyrim some things are, if not always plausible, at least
possible in the rules of the world. In Fallout when you do something impossible you only have two excuses, 1) It's necesasry for an ironic joke so we bent the rules, or 2) there is no other good excuse.
So, er, I think maybe the other answer is "We don't mind when they do it in Skyrim because we have no real respect for it as an RPG."