The problem is that spinners are a very niche product. I'm not even sure when a game company last made a spinner game, so the people buying them are all either BYOACers, or arcade operators doing repairs to old machines. Even in the heyday of arcades, it's not like there were spinner games popping up left and right (although there were some very popular games that used them). With such a small niche to fill, it's very hard to put out a quality product at a decent price.