I have no idea if these stats are true, but I've never understood why any town would allow foreigners to homes and leave them vacant. Is there any reason (other

I have no idea if these stats are true, but I've never understood why any town would allow foreigners to homes and leave them vacant. Is there any reason (other than 'yay capitalism') to not put more restrictions on who can buy and what they can do after it's owned? This wouldn't be a story if the homes were full of new migrants being added to the towns and buying big houses.