I see three possibilities here. One is that they thought it was silly to have obviously spent so much money on entertainment electronics and the environment they're placed in, but didn't want to have to say so. Another is that they know there's so much going on there that they don't know about, that they're afraid any comment they can make would reveal their plebian ignorance. The other is that, whether they know the costs and work and sacrifices or not, they just don't care. This might be hard to believe, but you guys have to remember that this is YOUR (and to some extent our) hobby, not most people's. Most people have smaller, simpler, cheaper setups than would be the most that they could afford, because they either don't care about the difference in performance or find the performance difference small in the practical sense (since they can already still watch the same movies themselves) and the difference in cost inordinately huge.
I can say this because I'm almost one of them; I'm actually somewhere between them and you. I've decided what the system I want is going to be like, and I know that some of you here would be scornful of how useless and inadequate it is... but I also know that to MOST people, my main problem would be justifying the expense, which will be more than most people spend (and would consider reasonable) but a little fraction of what it takes to build a home theater.
Maybe you'll understand the "outsider's" experience better if I give you an example from a hobby most of you probably aren't into: swords and other pre-gun hand-to-hand weapons. I've got a few on my wall right now. I'm a member of an internet forum where these things are discussed just as home entertainment is discussed here. I've learned a lot there, and it's gone into my purchases, and I think I've come up with some good solutions about how to mount these things on the wall. Most people know next to nothing about these weapons. Worse yet, most of what most people think they know is hopelessly false. Most makers and sellers of "weapons" out there are pushing overhyped junk, but most consumers don't know it.
Many people would walk in, see my weapons wall (especially after I've expanded my collection a bit), and think I'm a silly nut for having them, and think I was stupid for having spent so much money on them. If I were to walk in to the home of someone else who has collected the gaudy overhyped junk that tries to imitate weapons, I'd think (s)he was silly for having fallen for the sales pitches and not thought about things or investigated the facts better. But would my guest, or I as that other person's guest, want to say so?
OK, I am not intimidated by anyone else's knowledge about weapons, but I know that others have expressed to me that they know so little compared to me that they don't think they could intelligibly say anything worth my listening to. And I must confess to thinking similar things sometimes when faced with someone else's hobby, like leatherworking. I see so little leatherwork and pay so little attention to it that if someone asked me about his/her samples, and those samples didn't have any obvious disastrous flaws jumping out and screaming at me, I wouldn't know what to say; no basis for comparison, no idea what marks of quality I'm looking for, et cetera. So what could I say to such a person? I know it's common for people to feel that way about weapons when in the presence of a weapons afficianado, so applying it to home theater doesn't take much imagination. If you know you're ignorant, you tend to shut up and avoid demonstrating it.
And then there are the completely ambivalent ones, the ones who care so little that they'd hardly see it. They'd have nothing positive or negative to say about my weapons because they know people put all kinds of decorations on their walls, but they don't personally ever look at what they are, or see how a weapon on the wall is different from a painting or a ceremonial mask or whatever on the same wall. A home theater might be hard to miss to you, but to many people it's probably just a really big TV in its own room. I tend to be the same way about lawns. I know some guys spend hours watering and fertilizing and weeding and pesticiding their lawns and whatever else they can do to them, but I'd never be able to pick out their lawns while walking by; a lawn is a lawn is a lawn to me. I can't comment on what I don't notice in the first place.