I think my first Bethesda game was Skyrim and I love Skyrim. I’ve played through Skyrim when it first came out I played through it again in the DLC came out. I played through it again on the switch I have since played through it again on PC. I love Skyrim. I played it so many times and I know it’s a meme to keep re-releasing the game but it is just genuinely very good game.
I’ve played fallout three I tried to get into new Vegas. I played fallout four up to like level 40 just today actually and I’ve tried fallout 76. I know the gameplay is almost the same as the Skyrim game but I just can’t get into fallout and I don’t know what it is about that series . Maybe you can help me figure it out because I just don’t think this game is captivating.
It seems like there’s just less to do in the world enemies are Raiders or mutants and maybe some creatures and I guess sky rooms really the same it’s just different factions of humans but it just seems less copy and pasted than fallout does and of course Skyrim has the same dungeons, but so does fallout.
Is it just the genre of playing in a wasteland instead of a fantasy world the only real difference between the elder scrolls games in the fallout games? 
Time and your personal experience might be a factor.
Often the first book I read from an author, leaves a very positive and fresh impression, but after I read a couple more of the same author, I learn their structure and writing style, and it becomes just more of the same, and I have trouble getting into those books.
It is similar in other mediums as well, maybe to a lesser degree. TV series and video games have multiple writers to keep things fresh, but at some point it becomes just more of the same.
You can still try to replay/rewatch/reread the great ones, but then you know what to expect. This might not be the case with new media of the same authors.
Also time directly might also effect it, I have trouble really getting into any game now, because I have other stuff to do, and getting back into it afterwards (especially with video games) is more difficult.