So... the movie at least superficially confirms it. The lure language of the backrooms does serve a purpose, *it's to bring people in*. And it brings people in so that it gets more memories to expand. The more it expands, the more null zones appears, and the more null zones, the more wanderers to feed and copy from. It may not make the ISR more intelligent than a plant is, on the surface, but it certainly makes Async's problems more... complex.

We already had an inkling of this in the YT series, with the disappearance cases of the region seeing rapid growth after the stable opening of the first LPMDS. But the movie pushes this to new height, not one, but two birds in a few weeks / days. And what's worse... the entities becomes more detailed and sophisticated with time!   
The Bacteria was just barely able to maintain a wanderer lost, or keep it in place while it was read and recorded. But then the first Still Life came in, and by the time Clark got projected (as whatever he is really)... he was able to go back and phone Mary, to lure someone from *outside* of the backrooms. 

Not only this, but the ending with Mary's still life means that the Backrooms are not only content with copying the past. It either can project the future, or continue to draw from hosts long after they have been passing through!

Now if we do take all this together, this would mean that the rate of rooms being copied and fetched from the real world is increasing. Like Mary's reconstituted house, for example. The more people enters in contact with the ISR, the faster and better it copies stuff. We already had an inkling of this with Found Footage #3, but it remains consistent. 

So when Kane says he wished a TV series would be able to close that story... I'm left to wonder, what are the chances the null zones would become big enough so that the whole city around the Async's facilities would become contaminated?  
Since entities appear to be violent even with mere representations of humans (i.e. the cavemen), what if they gained enough autonomy to get out?  
What happens when the copying speed becomes exponential and we finally get a complete world of entities on an ever closer other side?

Food for thoughts...

Theory : Expanding speed of the backrooms?