Universal appeal ?

I finished reading Robinson Crusoe. Coleridge termed Crusoe the,"universal man", and I suppose that is why I laboured through the archaic language. I wanted to know what made a book appeal for over four hundred years.
I think I understand now what the "universal" appeal is. It is the lurking doubt in human hearts of, "What am I really, when everything extraneous is stripped away?Is there enough to this entity "Me" that I could survive physically, much less emotionally and spiritually? How much self reliance do I really have?"
Everyone can relate to these questions. Thus, Crusoe's " universal" appeal.