I think consumer sentiment in regards to interstate travel is quite low at the moment. Anecdotally many tried/did holidays in December when things opened up... then the Premiers intervened and closed borders. Especially on the VIC side, I think many will know or know of people who got caught up in that ridiculousness of 'dash' to the border around NYE or were a Victorian resident unable to return to VIC if they were in NSW.
If these sentiments ring true even "free" airfares wouldn't encourage travellers to visit NSW from VIC.
We still have a long way to go yet....