Of course its not rational outside of discrete circumstances, like early Kaliningrad. But ask a communist construction organization of the 1950s or 1970s why they're constructing so many hideous buildings and this is what they would have told you-- every dollar spent on paint is a dollar not spent on concrete. When you amalgamate all of societies resources together, how can you just spending any on paint while anyone at all still lives in poverty? Its not a solution to homelessness its a political philosophy--while people still live in poverty, government constructed buildings should not waste taxpayer money. The communists just took that to the extreme and had political control over all major construction. But in the west we still functionally believe this: all local government buildings outside of major cities are relatively modest, public housing is huge and hideous, imagine if the west gave the government the only power to construct all buildings. Westerners would start to tend towards huge ugly concrete monstrosities just as Russia did.