Earlier quoted context omitted.
New Zealand has just had to quarantine 1/3 of their population, again, because of 4 cases. Until the virus is contained everywhere you will yo-yo between closing everything and opening it. Unless we build a wall around every developing country this will be going on for years. The economy can bounce back from one quarantine, can it bounce back from 12?
They didn't "have" to do that and most places aren't yoyoing around, they're over it already and bumping along the noise floor of cases. NZ leadership has chosen this illogical and self-destructive path because they don't understand risk or data or, apparently, economics.
Most places aren't anywhere near zero cases a day. Both Australia and New Zealand were and have had to go back to higher lockdowns because there were breaches.