Choosing a game you like is a very personal formula, and theme is part of it. I own games like MET that took me years to buy. I didn’t want sweaty old guy band themes, but the rules and gameplay changed my mind. The theme grew on me, and now I love it. I don’t have examples of the other direction though. I guess the closest was Game Of Thrones, where I bought it too early because the play was “good enough” and I loved the theme.
So I’d say gameplay (physical and rules) wins over theme. But if theme is a hard no, then that can win.