Roughly 75% of the game is the same. And that argument actually makes a whole lot of sense. Its like socially acceptable and well recieved to bash 1 game to praise the other.
People who are objective will rank either game above the other but not by such a large margin. One thing NV didnt do better is the wasteland, it was flat and brown. It still has worse level design and quest design, less polish overall.
Except you are saying people are just preferring New Vegas over Fallout 3 because Bethesda made the latter. Your arguments are so bad that you don't know what you posted just a page ago.
Uh, you said you never played New Vegas because you said you were playing every Fallout game and still hadn't played the first two and New Vegas. So, how can you say that? Oh, wait you can't because you haven't actually played the game. You're most likely basing things again from the wiki, specially for the things i'm gonna say below.
Worse level design? Yes, seeing nothing but destroyed buildings, grey and greenish blue everywhere and copy and pasted, poorly designed metros is somehow better than a world that looks like it's recovering from the bombs. Oh wait, it isn't.
And worse quest design? Are you fucking serious? The quests in New Vegas are a million times better than the quests in Fallout 3. Most of Fallout 3 is nothing but fetch and kill this quests. New Vegas quests actually have different outcomes and a lot moral ambiguity. The fetch and kill this quests are a minority unlike Fallout 3.
Less polish? That's why i very rarely got any bug in New Vegas and crashed maybe three times in nearly 200 hours. While in Fallout 3 i had several bugs, including bugs in quests and the game crashed several times in just a single playthrough. And both versions were the ones with all the updates.
Just admit it, you're a zealous, fanboy of Fallout 3. Because that's why you say the game is flawed but when we criticize it, you just dismiss every single valid argument. That's what fanboys do.