Melbourne went from a peak of 725 daily cases to achieving 60 days with zero local transmission. Suggesting that all the lockdown measures were ineffective, and that eradication was entirely the result of circumstantial factors, doesn't pass the sniff test for me.
Given that the reduction in cases fitted closely with expected modelling, and only began after stage 4 lockdown was enacted, it's a logical conclusion that at least some measures of the lockdown were effective at containing the spread.
That's not to say that none of your suggested reasons weren't a factor, or that every single one of the lockdown measures were effective. But on balance, the lockdown and other governmental measures were effective.
Montreal is a city of similar size, wealth, and demographics to Melbourne, and has 88k confirmed cases, compared to Melbourne's 20k. That kind of difference is more than discrepancies in testing methodology and case definitions. Incidentally, ten days ago the city went into lockdown (although less strict that Melbourne), so if in a few weeks there's a subsequent drop in cases, I think that it will be pretty safe to make the conclusion that lockdowns work.
Given that the reduction in cases fitted closely with expected modelling, and only began after stage 4 lockdown was enacted, it's a logical conclusion that at least some measures of the lockdown were effective at containing the spread.
That's not to say that none of your suggested reasons weren't a factor, or that every single one of the lockdown measures were effective. But on balance, the lockdown and other governmental measures were effective.
Montreal is a city of similar size, wealth, and demographics to Melbourne, and has 88k confirmed cases, compared to Melbourne's 20k. That kind of difference is more than discrepancies in testing methodology and case definitions. Incidentally, ten days ago the city went into lockdown (although less strict that Melbourne), so if in a few weeks there's a subsequent drop in cases, I think that it will be pretty safe to make the conclusion that lockdowns work.