Como a individualidade ajudaria os estranhos a sobreviver?

Como explicado em este artigo da Film School Rejects , os comentários cortados do diretor abordam isso explicando que não há resposta para exatamente por que os estranhos estão experimentando - ou pelo menos nenhuma resposta que Alex Proyas (escritor / diretor) tenha alguma intenção de compartilhar.

Proyas left the Stranger’s reasoning behind the city and the experiment as simply “They’re looking for the human soul” in order to keep an air of mystery about them. “The film was more about the impact they had as a result of that experiment on human beings, so…if it begged for more answers then I always thought that was a good thing.” Proyas felt leaving the audience in the dark on a lot of the what and why of the Strangers made it a much richer film.

Não há resposta dentro do filme em si ou em qualquer corte diferente ao meu conhecimento.

Os únicos fatos que o filme afirma é que eles estão procurando pela alma humana, e aquilo que nos torna indivíduos, não os detalhes do porquê. Dito isto ...

A possibilidade mais provável é que a sua semelhança é a sua vulnerabilidade. Embora a extensão de sua mente coletiva pareça questionável (como você aponta, um indivíduo escolheu sacrificar-se), há pouco para distinguir um estranho de outro que não os cadáveres que eles escolhem para habitar e os nomes que eles escolhem junto com eles. Mesmo com isso, parece mais um esforço simbólico para se tornarem diferentes do que entender a individualidade ou, de fato, ser indivíduos. Há uma série de teorias nos círculos biológicos que a diversidade é o que permite que as espécies sobrevivam contra diferentes agressões ao longo do tempo. Então, em um nível genético ou mental, eles precisavam ser indivíduos novamente, e simplesmente não entendiam nada, assim os experimentos.

Eu prefiro a resposta que eles tinham mentalmente atrofiados para chegar aos seus poderes de sintonia, o que é mais sugestionável pelos temas do filme. Meu sentimento é o mesmo estado mental que fornecia a sintonização de cada um deles, mas impedia que eles concebessem ou desenvolvessem algo novo (você realmente não vê crianças estranhas, apenas cadáveres de crianças) e, então, suscetíveis à sua própria colapso.

Houve um prólogo extenso na novela oficial do filme. Em resumo, os "estranhos" são uma forma de parasita mental. Eles possuem poderes substanciais, mas sua incapacidade de pensar individualmente os limitou drasticamente.

Prologue

It began with a small thing.
A fragment from a passing comet spun into the dim gravity of their planet. With the fragment came a dormant organism. The organism revived in the dark, dry atmosphere. Immediately it began consuming vital elements in the home planet’s fragile ecosystem. And slowly began killing the inhabitants.
They were a race as ancient as time itself. Until now their species had had a life span in excess of a thousand years.
They survived by just being.
Unfortunately their life form had no need, hence no means, for migration to another planet.
So they waited. And they died.
The aliens were nearly extinct when a stray explorer wandered into their orbit. This time they were prepared. The moment the explorer craft landed, they penetrated.
They easily mastered the visitors by assuming control of their alien consciousness. Essentially they became parasites living through their hosts. Then they left their doomed world for their hosts’ home planet. But by the time they arrived, their life support had broken down. Many of their hosts had already died.
Eventually, all of the host species were exterminated.
However, using alien technology developed by their late hosts, they managed to manufacture life. They replicated their hosts—enabling the remnants of their own race to survive. Then their last numbers filed onto the alien starship and soared into the unknown. Without even so much as a home planet they had become strangers in the universe.
The Strangers came upon a variety of possible worlds to colonize. But sooner or later their hosts expired.
And too, the Strangers were empty of purpose beyond survival. From their various conquests of alien worlds they had acquired disconnected technologies, sciences and techniques.
But as a whole it came to the same thing.
Boredom. As a species the Strangers shared a common consciousness. Their thoughts were limited to function.
And as they traveled the disparate corners of the cosmos the Strangers found that most life forms were the same. Species existed to exist. Almost always in colonies.
For the Strangers, existence was an endless, mindless quest for a benign host. The concept would never occur to them, but in a strange way they were searching for the perfect lover.
A symbiotic relationship that would nurture new life.
On their own extremely rigid terms.
Because after all, they did not have the power to conceive, merely to consume.
Which was sufficient. Until they chanced upon a small blue world orbiting a minor star. The planet abounded in two elements that were lethal to the Strangers.
One was water. The other was sunlight.
But the species native to the planet was unlike any life form the Strangers had encountered in an infinite universe.
Their consciousness had . . . dimension.
At first the Strangers attached themselves to the minds of their new hosts. Immediately, both died.
For a thousand years the Strangers studied the Humans—as they were named. And their envy grew.
Humans had private thoughts. Incredible fantasies. Dreams. Music. And most fascinating—individual memories. In fact, the sum total of these memories formed much of their complex intelligence.
Not that the Strangers were without formidable powers. They had the ability to control time. They easily controlled humans by simply willing them to sleep.
The Strangers could also shape, bend and change most matter to suit their needs. But their very lack of . . . imagination, narrowed the scope of these powers.
And so the Strangers set out to acquire human memories. To possess them. To be them.
Methodically, night after never-ending night, they gathered in a vast godless temple. There in the underground darkness they activated enormous secret dynamos—and went out to steal human souls . . .