I think it stopped working once Covid became far more infectious. Before that, it was possible to stamp out the occasional quarantine failure.

I agree, it was definitely harder the second time with Delta. People broke the rules the first time as well, or mistakes happened, but the few breakouts weren't so difficult to contain.

It worked the same as it worked on personal level too. At the very beginning you can just lock yourself inside and there is basically no chance to get sick. But what then?

If you could just lock everybody in the world for a month you could basically get rid of all the infectious diseases. However you can't. So lock down only helps to win time.

After you win your time you really need to know what to do with it - e.g. effective vaccine is created in this time.

Otherwise you just delay inevitable and that is it.

That's what the government says when they fail, they blame the people.

It's your fault for not following orders, not our fault.

Our government was pretty careful not to put blame on the people honestly, it's really me that's blaming the people (I'm not the one that's downvoted you though).

The first time round wasn't the main thing that NZ basically shut itself off from the world? I was generally supportive of the sort of measures much of the world implemented restrict the spread of covid (widespread testing, masks, vaccinations, encouraging WFH, etc) however to me both NZ and China's approaches didn't seem feasible for most of the world.

So if I understand correctly NZ had a short hard lockdown to reduce cases to zero and then maintained it by severely restricting and controlling arrivals from abroad. I live in a Central European country that simply cannot seal itself off from the world like NZ did, we have open borders within the EU via Schengen (a good thing IMO) but there's very little chance of every country in the Schengen area agreeing to follow this model. This means virus carriers would inevitably enter the country, cause an outbreak of cases, necessitating repeated lockdowns and the public would quickly rebel against the measures.

That’s like saying that your grandma was able to keep per collection of 4 books perfectly sorted 100% of the time so why can’t a public library of 50,000 books?