Bethesda is incredibly non-creative:

*The BoS was supposed to be only present in California, and was dying out during Fallout 2, to the point where there was only one knight guarding a tiny outpost in a major hub. Then comes Bethesda: "hey, let's teleport them on the East Coast 36 years later. Also they have a giant robot that shoots laser beams!"

*The Enclave: completely destroyed at the end of Fallout 2. Bethesda:"Hey we need bad guys, let's teleport them to the East Coast along with the BoS!"

*Super-Mutants: supposed to have been created by the Master in California as part of the Unity project, supposed to have died out after his death at the end of Fallout 1, shown to be highly-intelligent, super-strong ubermensch. Bethesda: "What if we make them into dumb orcs, and they spawn litteraly everywhere!"

*Ghouls: humans that have been horribly deformed by radiations due to a genetic mutation, can't run cause they're basically walking corpses, still need to eat and drink. Bethesda: "Hey, that ghould kid survived in a fridge for 200 years! Also, let's turn feral ghouls into running zombies!"

*Bethesda during FO:76 development:"Huh-oh, we suck at coming up with new ideas, let's pilfer through the concepts for Van Buren (the original Fallout 3)!"

I could go on and on, like how Bethesda made nuclear weapons into something fun and recreational, in total opposition to the themes of FO1, FO2 and F:NV... You get my point.