On the list of things that would've gotten you burned at the stake as a witch, a mere 325 years ago, (the year of the Salem witch trials, 1693) we find:

Matches or a cigarette lighter (that person made fire in their hands.)

Anything aviation (that person attempted to fly)

Lipstick, fingernail polish, radio, TV, (that person listens to the spirits from other worlds), ballpoint pens, pencils.

Yesterday's "fiction" is today's reality.

You might want to wait a while, before declaring something unequivocally fiction or impossible.

True, in a sense that advancement of civilization has provided enlightenment.

Let's not forget that 'higher brain' animals tend to establish social structure.
Human beings are extremely social creatures.
Our need for social interactions 'could' change in the future but while it might be a possibility it is not a probability. Certainly not as abruptly as this film series depicts. In general, we actively value life.
There are exceptions but the ratio of the exceptions is insignificant to the whole. In other words, more people value life than don't.

I've read and heard enough that in some parts of the world there is little value placed on human life. The Purge films are not about those parts of the world, they occur in the United States and the United States is composed of people that DO value human life.

If the films were based in China, I might have a different opinion.
Population density devalues the human condition. As our population in the USA steadily rises the value of human life will fall. At present and in the near future tho, this is not the trend.

“Two factors are necessary for a resurgence of Nazism,” “a worsening of social conditions till they approximate those of the early thirties and the emergence of a Hitler-like leader. Should both these factors come into being, neo-Nazi groups around the world would of course become a focus of danger," -- Ira Levin: The Boys from Brazil.

Who needs ovens, when you can have the people "purge"?

And by the way, my earlier comments were regarding people I have "unfinished business" with. I would never purge on an innocent.