I think the reason people gravitated to F4 to blow things up instead of another blow-shit-up game is because F4 is one of the best blow-shit-up games in recent history. No other mainstream FPS is as open, interactive or visceral as this. It's not what Fallout is about or should be about, but it's what Bethesda made it, and they did it pretty damn well.
You have not heard of Just Cause 3 have you?
That game does explosions and taking down similar bases and enemies again and again right. One of the few games where I actually enjoy the repetition.
Fallout 4 is Far Cry and Skyrim together - the leader of first-person blow-shit-up games, and the easiest RPG to get into in the history of RPGs. They did both that well, I suppose. So I'll give them that. It's why they're such a success. Not much need for depth when you go for short-term wants.