Rebuilding an Old High School in Austin

From the a Allan Junior High in 1916 to Austin High School in 1925 to a campus of the Austin Community College in the 1970s and now being refurbished. I wonder how much the decision to keep the frame of the old building through the changes is because governments are cheep. Other old buildings, whether homes or government, have been slowly disappearing over the decades in Austin. How much does it matter to keep the old look and aesthetics and functions?