OK, I may have phrased that badly. By "product" I meant simply the physical item itself and by "vision" I meant "what that thing can do for you". It's possible to make a beautiful, well-designed and all-round awesome product that's still useless because it doesn't actually fit any real use-case that potential customers might have.
That makes more sense to me now. I lump that all together in 'product' whereas vision is more about where a company is going and what philosophy is driving it (if you get my meaning).
It is possible to have customers who purchase based on vision/direction but this pretty much the defining characteristic of 'innovators' [1], who are willing to take risks on unfinished or poorly supported products.