I would not call the new buildings "replicas", they are re-constructions by workers who still can build in the old style. So, they are not the original buildings, but they are built almost the same way and look like the original.

This is true for many towns and cities, in particular in Belgium and Germany. Many buildings were destroyed or badly damaged during the war and, after the war, the towns were rebuilt to how they were before. Other cities, like Rotterdam and Frankfurt, were so completely destroyed almost only new buildings came.

BTW, the German Wikipedia article doesn't say anything about Hildesheim building a new town until 1980 and then destroying the new buildings.