It had the dark humor and the setting. Retro-futuristic 1950s aesthetic, ruins of America, Pip-Boy, Vault-Tec, SPECIAL system, V.A.T.S, consumerism satire, quirky NPCs, Super Mutants, Ghouls, Power Armor, in-game radio stations with oldies music and DJs, Brotherhood of Steel, etc.

That's what makes a game a Fallout game. If it had none of that, but had intense roleplaying, would it have been a Fallout game?

Think of all the stories the game told. All the minor characters you helped. The depth of the companion quests. The mystery of the synths. I could go on and on about the stories and fun that were had. So I will!

The big twist regarding Shaun.
The Institute and synths turning out not to be a conspiracy theory.
Joining major factions: Brotherhood of Steel, The Institute, The Minutemen, The Railroad
Building and defending settlements
The Kellogg confrontation and memory dive
The Silver Shroud quest
Nick Valentine’s noir detective backstory
Cabot House and the alien artifact
Pickman Gallery and the serial killer subplot
Nuka-World DLC
Vault 81 and Curie
Vault 95 and Cait
Combat Zone
Diamond City and Piper
The Mechanist

And more and more! It was a huge storytelling game with tons of awesome content. That's what makes it a Fallout game. Not because you can choose to blow up Megaton or whatever. Actually, you could blow up the Brotherhood. Close enough.

All the negatives do nothing to ruin that.

How can you say what a straight face that it "lost everything that makes a fallout game...fallout". Nonsense.