We become so used to the noise around us that it becomes hard to notice that it is there anymore. I ignore road noise, turn the radio up, and only realize how loud everything has been when I slow down and find the radio painful to hear. Don't ask me about the air handling system at work.
This everybody knows, and most of us like to take a break in a quiet place in the woods. The difference is amazing, and refreshing.
We have the technology to make quiet rooms in the city. It isn't the same as the woods: the woods have their own noises. Still, imagine sitting down in a room (in a health club, say), where the only sound is your own breath, and resting for an hour.
I'm not up to speed on how to build a quiet room, but I presume you'd need to nest two enclosures, which would probably at least triple the price. The air handling has to be done separately, or at least run through a very large muffler. And, of course, you need to spend a little of somebody's time to monitor usage, let patrons know when time's up, etc. If a home costs $50/square foot, then guess $200/square foot for this kind of room. Skip any economies of scale by combining rooms or making common rooms, and posit a 100 square foot room (which may be a bit big) giving us $20,000 for the cost. Assume this is in an area close to downtown, so the hours of use are 2 hours in the morning, 2 hours around noon, and 5 hours in the evening on weekdays, and about 14 hours on weekends; giving about 91 (call it 90) hours of peak use time per week. Assume an occupancy rate of 1/3, for 30 hours per week or about 1500 hours per year.
The cost of monitoring the facility is some fraction of an employee's time (they have to also monitor handball courts, etc) plus cleanup time. If the club is open 20 hours per day, at 5% of the monitor's time that's an hour per day worth of monitor cost (say $20 per hour including benefits) plus another 1/4 hour of janitor time, for costs of $25/day.
I don't have a good handle on the relative return of different facilities in a health club, but let's guess that we want to pay for the employee time plus 3 times the installation cost each year. That gives us $40/hour plus about $2/hour averaged employee cost.
I've left some things out (furnishings and other amenities), but this gives us a ball-park lower figure. Are there enough people out there interested in paying $45 for an hour of complete quiet in the middle of a busy day in the city?
I'm not sure I would, but then I don't have a lot of disposable income.