Exactly.
The other thing to consider is that if you had a mansion (say 20+ rooms), you'd need more than a single set of mains if you were an enthusiast. What would be the point of having a mansion if you spent all of your time in one room? You'd need sets in the rec room(s), kitchen(s), bedroom(s), etc. I don't have anything near a mansion, but I do have 3 full HT systems (family room, master bedroom, guest bedroom) and 3 stereo systems (my home office, my wife's home office, basement studio) and will probably wind up with one more stereo system at some point (rec. room in basement) so the studio system can stop doing double-duty. My car also has a nice aftermarket system.
The hours I spend listening in my office are greater in number than all the others combined (since I listen while I work), and the car is probably tied with the family room, at least during the warm months (it's a ragtop). I could spend thousands in each room, but it just doesn't make financial sense. There's a lot more money in the system in my car than in the guest bedroom, for example. In fact, my car system is probably a good run for 2nd place with the master bedroom in terms of gear cost, not counting labor. At first glance this might seem odd, but it's all in priorities. There's little that makes me happier than driving 2-lane roads through the countryside on a sunny day with the top down and some great music playing. I could have spent less on the car system, but some of the constraints would have made me unhappy if I had... I need lots of power to overcome road noise when the top is down, it's a 2-seater roadster so the subwoofer was expensive due to space constraints (a Sunfire made specifically for htis car), you pay for theft-deterrent niceties and compact size, etc.
Of course, there are those (fools) that part with their money easily and are buying for bragging rights, but the fact is that there are few people that are impressed by $100,000 speakers versus a Bentley in the garage or just a very large empty garage. :-) I could spend a lot more money on HT gear, but I don't spend every waking moment watching movies and listening to music so it just wouldn't be logical (and most gear isn't a good financial investment, since most of it loses a lot of value as soon as it leaves the store and depreciates fairly quickly). I'd rather spend $100,000 on a classic automobile, home improvement, etc. Even those who have money to burn usually don't burn it or throw value out the window, and value is very personal (hence the poll, right?).
