>>The difference is not time but population density. There was probably never a time when you could leave your home unlocked and unguarded in urban cities.
There was and not so long ago (e.g. 40 years ago in Portugal or Poland. Probably many other countries). So I would change your statement:
The difference is not time but population density and specially politics/religion.
There was and not so long ago (e.g. 40 years ago in Portugal or Poland. Probably many other countries). So I would change your statement:
The difference is not time but population density and specially politics/religion.