The only time I can recall seeing a really high-end system in AD was a pair of >$30,000 Wilson speakers jammed in a room in the worst possible placement, and the other gear was hidden away.
The decorating budgets for these multi-million dollar homes is ginormous. One would think if they had that much money, they would have a dedicated hi-fi listening room (maybe combined with home theatre, if necessary). I think they easily fall prey to audio "consultants" who recommend expensive hideaway (in wall) installations. Muzak for the rich and famous.