I think the underlying issue is that NSW's strategy is different to that of Qld, TAS, SA, WA, NT.
The NSW Premier and various Ministers have repeatedly said that they are not pursuing an elimination strategy, that they are happy with some underlying degree of virus in the community - some of them to the point of 250 cases a day.
https://www.smh.com.au/national/nsw/cabinet-divided-over-lockdown-with-some-prepared-to-accept-up-to-250-virus-cases-a-day-20200725-p55fee.html
That wouldn't be accepted in any of those other jurisdictions given where they are at in terms of managing the virus. So unless NSW changes its stance and rhetoric and acts in a manner consistent with actually driving their case numbers down - instead of seemingly being happy to bobble along trying to manage the emergence of two to three new clusters a week - then I don't think borders will open to NSW for a while.
I thought it was quite telling this morning that the Qld presser gave forewarning to border residents to think about how they will operate in the event of a closed border shutting off access for even them.
EDIT: Me grammar gooder now