I'd expect it to peak with the poor and the rich and dip in the middle. My personal experience (not in NY, though) says it might look like this:
The poor are taking a break on their rent to live somewhere without a washing machine, and therefore need a laundromat.
The middle class have access to in building washing machines, and do their own. Because they're still under some pressure money wise, there's the element of social pressure not to be "extravagant" and get it done for them.
The rich are more time pressured than money pressured, and take advantage of full service options for their laundry.
The poor are taking a break on their rent to live somewhere without a washing machine, and therefore need a laundromat.
The middle class have access to in building washing machines, and do their own. Because they're still under some pressure money wise, there's the element of social pressure not to be "extravagant" and get it done for them.
The rich are more time pressured than money pressured, and take advantage of full service options for their laundry.