One quick hint: I assume that Coronavirus will become the next "flu". Through mutations the virus will annoy humanity for the next decades.
With vaccinations (which change as well each year) we will keep serious illness and deaths to a minimum. Again, I guess in autumn 2021 we will have a good vaccination infrastructure in place in all First World countries, where everyone can get a shot. At this time the UK, the US may open their borders again.
Ok, if New Zealand, Australia, Taiwan etc. want to keep the Coronavirus out forever, they need to keep their borders shut indefinitely. It's their choice.
The question is if these countries want to kill tourism/travel/airline off completely.