I think Bethesda got it right.
I agree, but I must also point out that the whole 50's theme was not Bethesda's invention, although I too think they did a splendid job in following the style.
Indeed the theme is what makes this game and thi series unique, there are countless scifi or futuristic rpg's out there, and barely a handful retrofuturistic ones AND perhaps but one post-apocalyptic-retro-futuristic game and series.
But I somehow know what you are thinking (or I think I know). One of my friends also never liked the music (but the Fatman bought him to this games side. Heh). I never asked him about the 50's style though.
To underline the key meaning: You can't please everyone, but you can damn well try. I conclude.