This will be a wall of text, I just woke up and had only a couple hours sleep so I can't think very well, I am also not a native English speaker and usually I am hard to understand when I type a lot (even when I am not this tired). I will probably start going in circles. Please read this imagining me calmly speaking. Text doesn't convey emotions well and I tend to rant, which might make people think I am angry aand shouting or something, nothing is more far from the truth.
Prone Squanderer, is right. The definition of a fanboy is being blind by the product/brand they "follow". So a classic Fallout fanboy is blind, but it might not be by nostalgia, it might be by many reasons.
The Nostalgia point is not applicable to most classic Fallout fans (real fans, not fanboys), nostalgia is wanting something from the past that you don't have anymore or remembering something (most of the time pleasant) from the past you can't have anymore, but most classic Fallout fans play the classic games regularly, so they are not affected by nostalgia (because they play the game in the present too).
Also classic Fallout fans are quite aware of all the flaws and problems on those games. They are fans because the know the good and bad about those but the good still outweighs the bad for them.
I thought that video nails it, and I am surprised he didn't even mentioned how Fallout New Vegas only had 18 months to be made.
Remember, that video is not saying that new games are bad (he even says the new games are not bad), that video is saying that new Fallout games are not Fallout games.
There is a difference between it's not a Fallout game and it is a bad game.
He points out quite well and clearly what made the first games Fallout games and how the new ones don't have any of it, or if they have a bit of something from the old games, it is just that, a bit. And that was the point of the video, it was a video for the 20th anniversary of Fallout and meant to showcase the history of the games and what made Fallout be Fallout.
He doesn't hand-wave stuff just because the classic games had it and the new ones don't. He mentioned all the things that were an essential part of the Fallout games. He also mentions what the new games do well or improved (like he says he prefers the FO3 speech checks being a % over the flat skill number of FNV, he mentions that FO4 has better shooting, etc). But what made these games be it's own unique thing in the classics was gone. Basically, what made Fallout be it's own IP was gone, and the new games focus on different things (and while FNV has a few of the classic things, it still lacks a few others).
Imagine that some other cult game IP was bought by a different company, let's say Doom was bought by CDPR. They grabbed the franchise and made it a third person action RPG like Diablo. Made it so you can play with the Doom guy and still kill demons and use weapons from the classic games. From now on all of the Doom games would follow that formula... That new Doom was not Doom anymore except in name. Same goes for if Final Fantasy started being visual novels instead of jRPGs, Call of Duty would become a board game, Minecraft would become a turn-based game where actions would take energy to do and you would have an energy bar and have to wait till it refilled to do anything else, World of Warcraft becomes a MMO text based RPG, Pokemon becomes a post-apocalyptic shooter where you kill feral pokemons, etc
Even if any of those new style games were popular and/or good, it would still not change the fact that those games were not Final Fantasy, Call of Duty, Minecraft, World of Warcraft or Pokemon anymore.
Now the same question can be asked about new Fallout fanboys. Are they blinded by whatever reason that they can't even recognize the good things in the classic games and can't discern any bad things about the new games? That they can't accept that the classic games were it's own thing and changing it so drastically totally made the new games not be Fallout games except in name? The answer is yes, because like I said before fanboys are blind.
New Fallout fans (not fanboys) will acknowledge the games faults and see how the new games are not really Fallout games, but they still enjoy these new ones and have fun playing it. They do not try to justify with mental gymnastics that the new games have everything the classic ones did except they are now not in turn and are in 3D.
It's the same both ways, Fanboys will always be blind (for whatever reasons) and shout as soon as someone criticizes anything about the product/brand they follow, while fans will know the good and bad about the product and can actually have polite discussions with people who criticize they products/brands they are fans of. It's how the world goes around.