How? Skyrim is basically post-apocalyptic in the way Fallout is supposed to be. The countryside is a lawless hellhole, war is everywhere but there are odd and awe-inspiring cities that are thriving despite the perils of overland trade. It has horses, it's pretty, it's vibrant it's visually interesting.
Fallout 4 is none of those things. In Skyrim 200 years have actually passed. There's a new dynasty, new kingdoms, new ideas. hell, the Imperials are becoming Italian, which is by far my favorite bit of world-building, There are old bunkers to be raided, sure, but they are isolated sideshows.
I can do EVERYTHING in Skyrim I wanted in Fallout 4 that I can't do in Fallout 4:
Ride Horses, look at pretty animals, fight for the soul of a nation and restore the old empire (America in this case, piss off Enclave), visit places that have developed since the end of the world (the end of the Tiber line in this case),
The world of Fallout 4 is a tomb, a dirty filthy hovel in the ground filled with Morlocks. Boston wasn't nuked, and yet Bethesda decided to make the entire east coast the Blackreach without ANY surface world.
The story is shit, but frankly, it's the world-building that makes this unplayable for me. Oh and while the MQ in Skyrim is as boilerplate as a waiver at the state fair, it's actually executed with a fair bit of flair, and love and certainly respect.
Although to be clear I LOATHE the Elder Scrolls because it's fantasy at it's very worst (even the stars aren't powered by fusion, they are literally tears in the universe.....fuck off game).