Given how few people we see (and it could just be off hours), it's hard to believe that the guy is making enough to do much more than break even after rent/taxes/utilities.
I'm assuming his grandmother owned the land, so there's no rent involved.
But yeah, I don't think this is a high-profit operation. It's a very small washeteria, so it can't ever be very busy. Four clothes washers and two dryers simply won't support much traffic, and it looks like the place is boxed in and can't expand. It will never be more than it is, a tiny sliver that's nice to have when you live nearby and your washing machine breaks down.
It is, realistically, very likely that a failed machine won't be replaced just because the business doesn't make enough money to pay for it.
... Which I guess is why the detergent machine in chapter 1 is there.
Edit: Though interestingly, the washers and the dryers are mismatched, and seem to be of different generations. Cover and color pages shows the dryers as that mustard-yellow that was very popular for appliances in the 70s and then ceased to exist, and the washers in white. Seems likely one of the washers up and quit in the 80s or 90s and they replaced all of them with newer smaller models, but couldn't color-match.