Street design

Am I insane, or we still designing streets they way they did when fresh sewage flowed alongside pedestrian walkways?
Since we have to get in and out of vehicles, walk, cycle, load babies into car seats, empty our trunks, stop to chat or cross the street, all at the curb side, why not design streets so that the gutter is in the middle? Why is all the water, oil and filth, drainage grills and debris directed to the only part of the street where people are on-foot?