Long before the current simulation fad began..
It was postulated that this was a "grown reality and universe"
Somewhat similar to say a hothouse horticultural research experiment. Or say ..a lab experiment and we are in the Petrie dish.
More stark were the theories surrounding the reason "why do this?"..
The most probable answers were...
not any "advanced" or divine reason..
But narrowed down to 2 most likely possible reasons.
1- there is more than one petrie dish in the lab...more than ones garden plant in the hothouse.
This is just one "place"....among many.
The purpose and why...
for which began as either "amusement" and "learning and education"...
Other petrie dishes ..or plants were to a lesser degree engineered with many safeties..
But the learning curve was shallow.
This one we are in was engineered to be dangerous...a challenge...and those entering ...upon leaving...did not return to the lab....to the hothouse...but went elsewhere...
Hence the curiosity....those looking for answers..those looking for loved ones who came here but have not come back....and explains the expansion of the numbers of the species .
A good few texts were written on this particular theory.
It also goes on to speak of the fact the lab...the hothouse...with fewer and fewer and finally no engineers to maintain it...
This place has become even more dangerous..
The garden going to seed...growing wild...and no one maintaining it...

The second theory is one that was far more dire...
The reason for this "construct" (frankly I like that term far better...since the whole current "simulation" craze is based almost completely on the context of computer code...whereas a "construct" implies any number of possible permutating studies to complete the desired "effect")
Anyway...the more dire reason for this construct being...that it was built by us in escape from either an environment that was completely inhospitable to life of any sort.
And / or ...was engineered as the most practical, economical , least resource consuming method of escape from the original creation ...due to depleted resources, planet wide or exo threat ..such as the sun flaring to the point of crisping us all..or any number of other cosmological accidents ...

Since space faring is costly...and time is the issue...
Since this method of micronization may be more practical for migration ...to provide us with an exact replica of the place we left...and the issues we had to face and have yet to face...
Buying us time to solve them...and possibly live happily here...possibly go back...
The big issue with that is...
Billions of years have passed here...
How much time since we actually "left" the last place...
A few nanoseconds? A few minutes? A few years?
If we break the petrie dish...
Would suddenly we be forced to deal with dillemas that we are unprepared for? That we technically just left mere moments ago?
What if it is an imminient catastrophic event whixh we fled which was unavoidable....but we bought ourselves trillions of years to figure out how to live happily here....or go deeper still into another petrie dish fleeing deeper still...?

excellent books...
I have them here in my library somewhere...