I don't think die-hard fans that trade off of established names aren't carrying direct profits. Especially for a franchise/studio as young as Moonlighter.
Die-hard fans keep the game's community alive, which can eventually lead to new people finding it, but I'd be surprised if even 50% of a game's revenue is supported by people that would pick the game out of a line up of all the game they plan in a year. And that other, indifferent 50% could realistically be snapped up by someone who shits out a cheap clone with a similar enough aesthestic.