I believe that loneliness comes from lacking people that are emotionally invested in you. The strongest bonds and closest relationships people tend to have are

I believe that loneliness comes from lacking people that are emotionally invested in you. The strongest bonds and closest relationships people tend to have are family (blood and marriage), which often come with a high cost to sever. The easier it is to walk away, the more superficial the relationship. Loneliness is a realization (or fear) that nobody is there when you need them. It isn't a modern problem, but modern life seems to be exacerbating it.