question of what came first. The hen or the egg.

Was it her cold, reserved unfriendliness that kept Emma away, or was it Emma who kept her away because of her cold reserved unfriendliness. :-D

We must not forget that Jane wasn't at Highbury most of the time.
When she does come it is to visit her family. Visits to Hartfield could only be an added bonus.

She has her own life with the Campbells. She was perhaps always conscious of it herself, when being cold and reserved with Emma *due to her negative feelings* for Emma of envy for Emma's position etc (which I'm assuming), long before the engagement.

Jane cannot be absolved of her own position as an individual and a person.

I'm wondering if Jane should have first paid Emma a visit on her return to Highbury?
She didn't have to push herself. Just behaved warm and friendly.
As a friendly warm person Jane would have never been neglected by Emma of that I feel sure when one analyses Emma's character(considering a combination of compassion and cheerfulness and kindness).

As for holding Emma responsible for her position, I think it would have been Mrs Woodhouse who would be holding that position of responsibility. Emma if remained unmarried would have attained that position much later.
In the course of the book Emma pays the price for her position to a very great extent in other ways.

Now as a married woman which brings on resposibilities and maturity, one could blame Emma for her lack of any 'sense of duty'.