Fallout is so much more aesthetically interesting than Skyrim. There are so many interesting sci-fi and modern things here that you can add and it will look appropriate.
Meanwhile Skyrim aesthetics are so terrible that modders don't even try to stick to them and steal things from The Witcher, Dark Souls, and Morrowind.
Or BS Argonia mod that openly stole concepts from one of the TR developers and when he came to say hi they started insulting him for no reason. Skyrim modders are truly subhuman.