The funny part is that even if you CAN hear them, you often won't be hearing them in your own space. I've written previously about when I bought my WB Arcs...I got them pre-owned from someone in my area, and in his space they sounded awful. If that was my only reference point I never would have bought them, but I'd heard them before at a dealer so I knew what they could do. Moral of the story - it's best to not only hear them, but hear them in your own space. If that's not possible, then yes there's a bit of faith involved, no way around it.
But as has been said so many times, you often do get what you pay for. In my case with the awful-sounding Arcs, I had to stop during that session and remind myself that I was listening to $6500 speakers that had been on the market for more than a decade with happy listeners all over the world, and that what I was hearing was not what I should hang my hat on. And I was right - got them home, and they're superb. But there was some faith involved...not just wishful thinking, but faith that the many who'd gone before me and spent $6500 weren't all crazy. It was like in "Lost Boys" when Kiefer Sutherland said about the rice "how could a billion Chinese people be wrong"!
So yes, many of us have purchased based on reviews, knowledge, word-of-mouth, etc. and had it work out just great though we all know that in a perfect world we would prefer to test everything in our own room with our own equipment.