This is what happens when a movie prioritizes subtext over the story. Movies like this are contentious, with some enjoying dissecting every aspect to find a hidden interpretation, preferring it to a more traditional film experience. Call it an acquired taste, which is to say it's something bad that people only get used to through repeated exposure. There's a few movies like this that I can't stand, but this is so far the worst, most egregious example of this trend.
Disregarding everything this movie attempts to communicate about modern life, relationships, family, raising a child, etc: It says absolutely nothing about the logistics of its premise, or otherwise anything that would give you an idea as to how the story is even happening.
(((SPOILERS)))
There is some kind of otherworldly being presenting itself as a realtor in order to kill people, presumably to sustain itself. This entity has people enter a large urban development, its domain, and traps them there somehow, holding them for months, making them raise a replacement alien realtor to take the place of the original once the people raising it die suddenly.
The countless flaws in logic that arise with the existence of such a creature are self evident, yet the movie rolls with them in service of its themes. I simply can't suspend my disbelief enough to excuse a concept so divorced from reality, and if anyone says they can, they're fooling themselves.