Complexity in just what I and doing right now is impossible to comprehend. Imagine a mobile app with dozens of dependencies taking on a "secret" project involving a dozen of those dependencies that are drifting far way from the rest, with a dependency manager unable to function in this circumstance requiring manual guessing of what goes with what. Now imagine trying to develop with this Frankenstein set of dependencies and have any hope of getting work done. Of course the problem is not technical, its institutional; yet it's an unreasonable well of complexity that belies the demands placed on its workers. Technological complexity is not the only kind to worry about, it's the difficulties of managing complexities that are not obvious and cannot be explained to non technology savvy executives leading to painful results.

Now add a wealth of server side complexities with webs of micro and not-so-micro services interdependent on each other made by teams further and further removed from each other leading to more instability and unpredictable behaviors.

Managing systemic complexity (or not doing it well) seems endemic to programming today much worse than when Brooks wrote his essay (and I actually predate).