Many Northern hemisphere punters transit HK as a hub for Aussie and NZ (and vice versa); CX offered a wide range of destinations at both ends of the world. As Aussie and NZ are going to have their borders closed for the foreseeable future those saying things will be back to normal in 2 - 4 years will be eating their words. Nobody is really going to want to fly half way round the world and then have to be in quarantine (in the NZ context at NZ$3000 for the privilege) before having the holiday or family visit.
There have already been mutations of the virus and people who have been infected a second time; the long term consequences affecting health are starting to emerge too. Sadly this has screwed everything we knew before 2020