In this model (very abstract), the world starts with a bunch of nodes (actually self-sustaining processes) that act for their own reproduction, however that happens.
When there is a reason to do so, one node connects with another to exchange food, goods, information, whatever. These first connections are done less because of need and more because of the ease of connection. Maybe I form a relationship with a farmer at a farmer’s market to get vegetables that are hard for me to grow for myself.
Over time, especially with the growth of population, more and more of these connections are made. This process is fairly straightforward until we have to change a connection.
Maybe the farmer dies, and the family leaves the farm, and it’s turned into a housing development project which we don’t need.
Needing to change a connection can also occur because of changing technology (stores instead of individual farmers). Whatever the convenience of the new connection, it will almost always be more complicated than the one you had before, and there are additional costs associated with making the change and using the new connection.
This is the kind of change in a system that leads to aging at the large system scale.