-So that's one guy. Hardly "every romance ever". Which guy? Spoiler tag it for me.
-Starter city? What? Is this Mama Murphy at Sanctuary? If that's the case, she's a drug-fueled psyker whose narrative purpose is to provide a certain side option for the main quest. Just. That's the point of her being there. If it's Diamond City or wherever, I have no idea what you're talking about.
-Of course the main story is about how you want your child back, because it is literally entirely about retrieving your child from the scary infiltrator robot people. As I recall it, there's far more MY BABY IS GONE than MY HUSBAND IS DEAD in those dialogues, certainly not every time.
-So the Vault Dweller has no canon personality or backstory? The Chosen One, his grandchild, doesn't, either? The Lone Wanderer isn't a vault dweller chasing after their disappeared father? I have precisely zero idea what Fallout games you've been playing, but are you quite sure they weren't total conversion mods?
If there's anything shocking here, it's that this whole thing is so thoroughly cherrypicked.