What Makes a Poem 'Great'?

[~Ji]

I have been reading some poetry by Australian bush poet John O'Brien from around 1900.
O'Brien's poetry is earthy, colloquial, jocular, camp-fire stuff. Highly enjoyable, but, in my view, probably not 'great poetry'.

I have just read another reader's response to his poetry who has made much the same comment.

I can sense 'great poetry', I can feel 'great poetry' emotionally; but I cannot describe what makes it so.

So, what is it? Or is this question sort of asking, what is the meaning of life?

[Pompey Bum]

The meaning of life is to turn yourself to the Good despite the world's depravity and your own. But great poetry remains a mystery. :)

[Pompey Bum]

To be a bit more serious (not that the meaning of life isn't serious), what you are observing with your bush poet may be an inherent discrepancy between virtuosic and folk art. These categories carry a lot of social and political baggage and are subject to sweeping changes of fashion. Personally I enjoy both.