I was playing a survival game today and had reached my second year, when i allowed the mobs to get into my base and destroy it. Upon destroying my castle i got a prompt to rebuild it, once i did this it began spawning in new villagers and resources like when you start a new game.
I haven't tried to reproduced this yet but i would assume the game ended when the mobs destroyed your town centre, so allowing someone to rebuild it might be open to exploiting to get lots of early villagers by letting it be destroyed a few times.