try growing stuff on a city balcony. assuming sun and water, it'll grow really well, due to the urban heat island.
However when you get pests, thats it, game over. you've got black fly, and they are never going away(I tried sprays, buying ladybirds, nematoads)
Why? because you only have one tiny portion of the ecosystem that is based on pests. Most pests are way down the food pyramid.
Now, I moved to an allotment, with a huge range of crops, which has a huge range of pest and predators. I had black fly for a week, and then the ladybirds came.
Why? because pests are seasonal, you need broad range of pests to keep the predators in any useful numbers.
As a king, what would you prefer - to defend against one big kingdom that wants all of your land, or to defend against three big kingdoms that each want a third of your land?
When number of points of failure trade off against your attack surface, you can't just say "more PoFs is better".
If we were to use that analogy, a more accurate metric would be either having 1 large centralized kingdom or 100 small, autonomous, independent kingdoms that each have fundamentally different weaknesses. If one fails, you still have 99.
But even that fails to understand the dynamic of biological systems. There's mutually beneficial, symbiotic relationships between crops and many creatures (bees, worms, etc).
Presenting it as always in conflict is inaccurate.
The fundamentally different approach is to not look at pest solutions through a genocidal chemical warfare lens but instead to figure out how to maintain a sustainable relationship and have all of nature working for you instead of setting most of it as against you.
In context of sustainable ecosystems, I agree with your detailed explanation. Controlling and maintaining a complex system of feedback loops (that we still don't completely understand) is a very difficult task though, so I'm not surprised that currently the most crude methods (genocidal chemical warfare) are also the cheapest / most efficient.
I wonder if this isn't a good field to benefit from computational models though - from tools to design, predict and manage natural feedback loops in agriculture. I don't know, maybe it's already a thing in the industry?
Blanket chemical warfare is like feedback linearization. Wasteful in terms of energy and has other flaws associated with stability. There is a better approach, e.g., passivity based control, which requires understanding the underlying nonlinear dynamical system.
Interestingly this has been the same problem in medicine. However, there are more nuanced control-oriented medical techniques being developed (need better observers and actuating mechanisms).
The gist of it is that in balanced ecosystems, you have natural remedies against pests; birds against insects for example, or certain plants that repel insects, or plants to combat diseases, or predators that eat insects that distribute diseases.
This is the theory; currently there is little evidence (as in, scientifically valid results, not anecdotes) that this works as it's claimed. I'm working on an experimental food forest to test some of these concepts. There are many things I'm very skeptical of, but in the mean time I have an excuse to work outside in the field, so hey...
Every culture faces multiple classes of pests: virii, fungus, bacterias, nematods, insects, rodents, birds...
What is good to control a pest can be beneficial to another since they compete for the same resource.
In the intensive context of monoculture, losing a battle often means losing the war.