Except that all the uncontrolled spreading you are so worried about has its origins in supposedly controlled HQ program. There are positive cases in the AO cohort so some low risk of virus escaping remains. But risk from Sydney is also low (if it wasnt we'd be seeing spread in regional NSW), and many exempt people still travelling from there everyday such as truck drivers.
The best controls are still behavioural - keep distance and hand hygiene.
Sydney is not and has never been in the utter state of disarray that Melbourne was, there isnt mass unchecked spreading happening, the numbers dont support that.
Closing internal borders becuase of a handful of cases does more damage to more people economically and mentally.
Widespread vaccination has significant benefits but it wont guarantee the vulnerable wont get Covid, and it certainly wont mean zero cases. We have had flu vaccines for decades, and we still see flu deaths amongst the vulnerable each year.
The discussion was the difference between border closures, and having AO players in hotel quarantine. In the former, once the virus is out, it is potentially uncontrolled. We don't know if there's been a super-spreader event. Infected persons may have gone to multiple venues. In the case of AO it hasn't brought in potentially infected persons and allowed them free movement. They are strictly controlled.
The escape of the virus is a real risk, but a separate issue to border closure vs HQ.
Agree vaccination won't mean zero cases. But like the flu vaccine, society has accepted, on balance, that we will accept some risk. If the vaccines are successful, why would our risk appetite to covid be different to the flu?
All governments including the Cth have stated this is a health issue first, the economy is second. Agree people were caught out in this latest round of border closures, but people are probably less likely to travel interstate for a holiday in the short term.