The municipality could service all the homes and pay for it with taxes, probably using their own people or a negotiated contract.
The private (and usually no -savvy) individual has much less negotiating power and is going to get taken to the cleaners by a plumber. Three houses in a street are likely to have 3 different plumbers on 3 different dates.
It’s just like that the cost per square foot to pave a single driveway vs the entire sidewalk or foundations for a whole neighborhood.
The municipality could service all the homes and pay for it with taxes, probably using their own people or a negotiated contract.
The private (and usually no -savvy) individual has much less negotiating power and is going to get taken to the cleaners by a plumber. Three houses in a street are likely to have 3 different plumbers on 3 different dates.
It’s just like that the cost per square foot to pave a single driveway vs the entire sidewalk or foundations for a whole neighborhood.