I feel like everyone is talking about Melbourne's lockdown as if it was their first lockdown.

This is their second lockdown. They virtually eliminated it during the first lockdown and brought the virus back in via hotel quarantine leaks (as proven by genomic testing).

There is nothing indicating that the same thing won't happen again. NSW's contact tracing team has been excellent but I have not heard anyone detail how Victoria's team is up to scratch now (a part from throwing some money at Salesforce).

There is no long-term strategy in this whatsoever, the hope is that the vaccine is available and effective before the inevitable 3rd wave hits a still highly susceptible population.