I see no reason why people wouldn't be interested? Literally none. This is how brands work. It's from the people/company/world/etc. that you already know.
Like Game of Thrones? Well this is related to it!
Ok, show me.
People watched 'Fear the Walking Dead', it's not the same kind of hit as it's parent show, but people watched it. Spin offs and sequels are made for precisely that reason.
I don't think it's the uber fan that matters, it's the casual viewer who likes the show and will be open to something that may give them the same sort of thing to replace it.
If people don't like it once they've seen it, fair enough, but there will be interest.