This is indeed a big assumption. We have been able to create new systems from technology but are humans capable of reverse engineer complex biological systems or emulate them effectively is a complete unknown. For example, there are few groups trying to simulate a single cell for decades, and we are still extremely nascent in our ability to do so.

It is possible that there are many facets of reality that are simply outside the comprehension of human brain. In fact, is is likely that most reality is outside our comprehension.