Because of this, systems can be sustainable. Programs cannot be. They are constrained by the laws of thermodynamics. Systems are the only source of resources. They are the only source of profit and wealth.
Programs are merely channels for the expenditure of resources generated by systems.
Systems can be self-regulating. For example, consider cybernetic systems like the human body such systems rely upon a limited number of inputs and adjust their operations to optimize the use of these inputs. Programs always require external regulation, and there are no inherent mechanisms to regulate programmatic operations. As they do, the system as a whole naturally becomes more internally diversified . And the diverse elements of the system become more complex and interdependent .