Lonliness is internal: we are brainwashed to believe that if we aren't having someone, we then are lonely, iow, "alone" and "lonely" are falsely drummed into us as being identical.

If one has emptiness in one's self, then another loving one can't undo that: we have to earn honest self-acceptance, ourself.

I think most of the "relationship" and "mental illness" problems of the current world are really produced by preventing people from earning self-understanding & self-acceptance.

People who live among nature, nature may force them into knowing themselves.

but with all of our lives, not just all of our adult lives, but all of our lives, for-profit distraction doing everything it can, to prevent us from turning from consuming to instead understanding ourselves .. why would it be surprising that loneliness becomes rampant?

It took me years to break the "alone == lonely" programming, and self-acceptance was the key to doing it.