Well, Bmpnyc did somewhat imply that the trickle down effect was at work here, but I think you're short-changing much of his point by highlighting that. To basically say that, with discretionary purchases, we each have different points at which we feel the purchase is unwarranted, and that this point varies with the person, their conditions, and the specific purchase would suffice, IMO. To bring morality into the conversation (at a specific price point no less) is certain to draw a rebuttal saying, "I'd spend that much and I'm not immoral".
Just out of curiousity, if it's not "right" to buy a $100K system (for whatever reason), is it wrong to sell somebody a $100K system for the same basic reasons? If people feel guilty for indulging in something that is clearly a luxury, is there any sense of guilt by the people who facilitated it's existence?
To answer the original post, I'm not rich, though I do work in a Wall-Street related position. I definitely spend more on A/V gear based on having more discretionary money than I did in the past. I love the hobby, but am probably not as fanatical as many who post here, and definitely haven't made as many sacrifices as have been described here. By being interested in the hobby I have, as others have suggested, put together a system I'm very pleased with for far less than a similar system would have cost had I walked into a high end shop and said, "set me up!". But to me, it's all about prioritization - a high end music system, purchased with care, is a tremendous entertainment value - you can use it 365 days a year, very little maintenance, and highly enjoyable. Many of my friends have boats, more exotic vacations, more expensive cars or clothes, whatever - I don't think they're crazy for how they spend their money and I think I've convinced most of them that I'm at least not crazy for spending mine the way I do. In any case, if you're interested in getting to that next level of audio nirvana and not spending an arm and a leg, there are many on this site who'd be happy to offer their advice!