I know, from personal experience, that one cause of loneliness is expecting that life should come to you.
In truth, everyone else so tied up in their own lives that they don't often go out of their way to find others who need company. If you are lonely it is because you are not out there looking for life.
Looking for life means looking for an opportunity to give something of yourself to someone else. I know this can be hard if you are old or infirm, but plenty of lonely people are young and healthy.
You have to invest to get a reward. Give the best of what you are and life will give it back many times over.
Thank you for the meaningful comment, @vortipor.
Yes, people often do tend to feel powerless and just despair instead of taking action to solve their overarching problems. Often, we need very little effort to achieve something but we are too afraid to do it or we are too much convinced that something as natural as finding friends is impossible for us.
I see that you're new on Steemit, good luck! 😊