There were indeed excess deaths due to bushfire smoke in Australia, a parliamentary enquiry was told it was about 400 people in all - in January and February. So it precedes covid/lockdown effects.
Someone infected today will take 4-7 days to show symptoms, another 1-3 days to get tested, and 1-3 days (up to 10) to get results. Thus the standard has become that any new restriction introduced, or any restriction lifted, it'll take us 14 days to see if it had any effect on case numbers. So if something is introduced today August 18th, it's not going to help someone who was infected last week.
Looking at the graph, take the measures and shift them two weeks to the right, and you can see which had what effects.
In the first surge of cases, quarantining international arrivals had the single biggest effect, and after that stage 2 restrictions - no big wedding, football games, etc. Stopping people going to playgrounds or cafes etc had no effect, because the caseload was so small - if even 1% were infected (which would be 64,000 people in Victoria) that'd mean a few visiting a McDs each day and possibly passing it on, but it was more like 1 in 10,000, so the restrictions after stage 2 did nothing.
In the second surge of cases, the numbers of people infected and out in the community were higher, and so tighter restrictions such as closing cafes could have an effect. And that's why we see that stage 3 and wearing masks caused the cases to drop. Stage 4's effects, if any, will be shown in the next week or so.
However, the caveat to both stages 3 and 4 in this case is that the cases were mostly confined to a few workplaces. The ABC link below gives a nice graphic of the clusters.
https://www.abc.net.au/news/2020-03-17/coronavirus-cases-data-reveals-how-covid-19-spreads-in-australia/12060704?nw=0They're in healthcare, aged care, meatworks and warehousing, and a little bit in schools. Apart from closing the schools, the general restrictions of stages 3 and 4 didn't affect these places at all. However, some targeted measures such as PPE for abattoir workers and reducing staffing in meatworks and warehousing, along with restricting aged care staff to working at one facility, have slowed things down.
That said, the virus is simply burning though victims - if you shut down a workplace with 60 out of the 100 people infected and make them isolate themselves, you only expect at most another 200 or so cases from it - the other 40 staff, and the households of all 100. So it may not be stages 3 and 4 at all, it may simply be that we're identifying where there are outbreaks and containing them.
Long-term, that's what we need to do: get good at containing outbreaks. Doing what Taiwan etc did from day one: test, treat, track and trace. This is a useful thing whether we have lockdowns or not, because that way old Gladys might die, but Maeve doesn't. Currently they're both dying. But they're not dying because someone goes for doughnuts at 9pm or cycles for 65 minutes rather than 60.
But just looking at the graph, what you should get from it is that stage 3 gave us a decline in cases. Now, stage 4 may give us a more rapid decline, but I doubt it because it doesn't affect the places where the infections are actually happening. Which is why CHO Sutton rejected it on July 25th. Unfortunately, a politician is in charge, not Sutton.