A fence is a structure that people have been building since ancient times and which has several directions of evolution.
Yes the more advanced the country the lower the fences between the houses until they completely disappear, only an imaginary border remains and vice versa where people thought that the fences were no longer needed the understanding comes that there should be a fence between you and your neighbor and how can you higher moreover with many degrees of protection against encroachment.
Often a fence is something that a person forgets about after its erection and the fence begins to live its own special life. It would be more accurate to say that the life surrounding this fence will gradually squeeze it and strive to demolish this barrier regardless of what this fence is made of.
Nature struggles with wooden boards quite quickly and they become part of the biosystem when mosses oxen and mushrooms grow on them but steel takes longer to tinker with.
I think that you did not try to chew a steel nail, we would not really like it but nature has its own gastronomic preferences and it makes attempts to swallow a steel fence which is already partially absorbed by the wood of an old tree which you can see in this photo .