Even if you have the money, if the setting book doesn't interest you, don't buy it. I don't think that will impact books for other settings being released though it might mean that any plans for an expansion book for that setting is scrapped if the numbers are low enough.
Maybe not, but if they were contemplating doing that, poor sales might make them think again leading them to take whatever mechanical options they've already created and fit them into a different book. Otherwise, I don't think the sales of a single setting book will affect them in terms of what other setting books they choose to release.I don't think they will do follow in support books regardless.
Is that because you don't find the style of writing in setting books difficult to translate to the game? Or because you feel the novels provide important setting information? If it's the latter, the Eberron novels aren't canon, but if you were to pick up a series the general consensus is that Don Bassingthwaite's books are the best Eberron books (Everyone loves Keith's worldbuilding but Don is a better novelist)
It depends, limited funds no, if you have a reasonable amount of money to burn then yes.
Settings books good cause most time they have info that is not republishedI have bought the Eberron book even though I am not a massive fan of the setting. I enjoy reading but never really ran it except using Stormreach once.
I don't actively dislike it either though.
My logic was it encourages WotC to make more settings books. Settings I do care about. Assuming you care about other settings.
Now I would also apply this logic to settings I actively dislike those being Ravenloft and Dragonlance. There's no point where I expect WotC to change those settings to fit my tastes because that would lose them their current fans. There's probably something in them I can use.
Now I don't use this logic on everything of course. I'm not going to buy a bad game to support a franchise just because. The difference here is I care about some of the old settings and a few haven't been updated since the 90s.