The main Post Office on the corner of Union and Park streets served the city well for decades. In the late 1990’s it was moved to the middle of nowhere in the most inconvenient place possible almost in another town. My guess is that some city official had a brother-in-law that needed to lease out some property. The “unable to update” argument is nonsense, the building is in use today and it could not have been more expensive than building an entirely new one!
The image above is of Joseph E Langlois leaving Attleboro for Washington DC. He was going there to be named Postmaster of the Dodgeville Post Office that was located just to the right of the main entrance to the Dodgeville mill. Part of the foundation for the building is still there along the retaining wall between the parking lot and South Main Street.
(He was also my Grandfather.)