Some systems require a total commitment to the complexity because it is intrinsic. There is no "simple" form that also works, even if poorly. In many contexts, "systems thinking" is explicitly about the design of systems that are not reducible to simpler subsystems, which does come up in many types of engineering. Sometimes you have to eat the whole elephant.

There is a related phenomenon in some types of software where the cost of building an operational prototype asymptotically converges on the cost of just writing the production code. (This is always a fun one to explain to management that think building a prototype massively reduces delivery risk.)

This is the point we are at now with wide-scale societal technologies; combining the need for network effects with the product being the prototype, and no option but to work on the system live.

Some projects have been forced so far, by diverting resources (either public-funded or not-yet-profitable VC money), but these efforts have not proven to be self-sustaining. Humans will be perpetually stuck where we are as a species if we cannot integrate the currently opposing ideas of up-front planning vs. move fast and break things.

Society is slowly realizing the step-change in difficulty between projects in controlled conditions that can have simplified models to these irreducibly complex systems. Western doctors are facing an interesting parallel, now becoming more aware to treat human beings in the same way--that we emerge as a result of parts which can be simplified and understood, but could never describe the overall system behavior. We are good examples of the intrinsic fault-tolerance required for such systems to remain stable.