I think it somewhat depends on whether you have an out-of-the-way dedicated listening room or if your system is set up in an accessible place. My system is set up in a room with no windows - I find it comfortable (and private) and it's perfect for HT, which I also love, but it's not easy to drag somebody down there to listen. If it were in my LR, I think I'd get more takers.
I also think that most of the comments one gets about their system are inversely related to how hard they push to get somebody to listen. If music just happens to be on and somebody new hears it, I think a large percentage of them would either make no comment or notice how good it sounds. I have had very poor luck, and rarely try anymore, in trying to get somebody to appreciate how good the music they like can sound.