An episltary novel was told in letters, and was something of a multiple p.o.v. You have letters people wrote to people, letters those people wrote back. There are a couple of theories about why omniscient p.o.v. became less popular. I think there is also something to the fact that Ernest Hemingway and Raymond Carver wrote naturalistic fiction and used third person limited really well and that the style lends itself to establishing a sense of psychological realism. The people in the stories seem human and full of foibles and the lives they live are often not particularly glamorous.
Naturalistic style is only one style.
Psychological realism is a great way to tell us about ourselves but it is limited. We don't talk in poetry, poetry is rarely realistic to the way we use language, but poetry is still an amazing medium to illuminate, and in the same way, conventions other than psychological realism can do things that psychological realism cannot. Tarot cards and dreams tell us things about ourselves because they sneak through our assumptions. Magic realism can do the same thing. So can omniscient and lots of other styles that are getting more and more accepted.