There was as service that did this in my old neighborhood. Occasionally when I'd go for a walk, I'd see laundry hanging on someone's door. (It was a old downtown area where front doors are basically right on the sidewalk.) I think it was clean stuff because it was nicely hung. The group was also discussed in my Buy Nothing spin-off group.
Would you have set pick-up/drop-off days for certain areas to keep down your driving costs and time? So if I live in the northeast quadrant of town, I can only leave it out on Tuesday and get it back on Thursday? Or can I pick my own days? Is it s subscription (or is there a discount for committing to something weekly for a term of several months)? Would your drivers drive company vehicles or their own, and have you factored insurance for that into those costs?
And do you plan to work the cleaning line, or hire it all out? Are you willing to fill in when someone flaks, quits, or calls in sick? With lower paying, relatively unskilled labor, finding reliable long-term labor might be one of the biggest challenges. It sounds like you would be paying in the higher end of the spectrum, which will help, but having a plan for when someone doesn't show up and you have pick ups to make and laundry that needs to be processed, is probably necessary.