> where extinctions occur because the environment changes such that the system is no longer optimal
What if we looked at the extinct species as constituents that have been removed because they were obsolete in the system? That way, the system remains optimal, without resisting change.
The system of humanity requires a lot. We used to say "survival of the fittest", which meant survival of the fittest and the "most aware", meaning being able to distinguish which survival strategy is the most viable for a given organism.
Fight, flight, freeze, dominance, independence, submission, DIY, DOBUY; the latter are especially interesting given how reduced information about the requirements and the sensitivities of the individual body can cripple your organs to a point that is more beneficial for some interest group than it is to you; in other words: someone can make sure you are stupid enough to be abused for some specific task until you can be discarded of. At this point we don't know if the system will survive more than one period because of the interest group or suffer within one or more periods because of that interest group.
In evolutionary biology, more symbiotic organisms and systems survived a lot longer that those who were less symbiotic, on scales that modern humans can't put into adequate numbers yet.
Isolated systems do exist. They can be isolated and they can self-isolate for various reasons and by various means. This happens even in species/systems we mostly consider mostly unconscious while definitely sentient and aware.
Wear and tear and maintenance, leeching and seeding, putting info and questions into words and lurking; none of these really attach a system to another by default, by design or via behavior, reward and punishment. The rules go beyond that and stretch longer time frames than we account for.
Thinking out loud here, btw.