They can also push other Five Eyes countries to follow up, and Japan too. Korea might be difficult to persuade but hey we have a military existence over there.
After all, Five Eyes + EU + JK is pretty much THE non-China market out there. The others are not rich enough.
Since Australia was mentioned, let an Australian tell you something about the history behind Australia economic policies.
Australia experienced boom times after WW2. It has a strong manufacturing industry. It's not well remembered now, but back them agricultural machinery designed and made here was regarded as some of the best. But we aren't a big country, so economy of scale did not work in our favour.
We responded by raising tariffs. It saved the manufacturing base, but that's the only good thing that could be said for it. Every other economic indicator was going backwards. After a few decades of that a politician named Paul Keating famously (well, it was famous here anyway) said the policy was turning us into a banana republic [0]. We made him Treasurer, and later Prime Minister. During that time he tore down tariffs, and removed other non-tariffs barriers such as the one our bank system hid behind.
The policy had a rocky start, climaxing in the recession in 1991 Keating said we "had to have" and interest rates hitting 18%. Unlike the USA where fixed interest rates are common, in Australia that means everyone is paying 18%. I remember it well. The memory still hurts.
It's 33 years later now. We have not had another recession. 33 years of continuous growth. The free trade policy is pretty much set in stone now. We dismantled what was left of our car manufacturing industry a few years ago. Everything we do have to be world competitive, or it goes. Did you know Google maps is Australian? There were do satellite mapping companies at the time. Google bought one. The other one, Near Map, is still turning out better satellite maps than Google.
Anyway, the point is if someone pushed Australia to close it's economic borders they would get one mother of a push back.
Although I don't disagree with you (considering my knowledge of Australian economy is very little), I do think that national security would override pretty much everything else in the next few years. The golden boat has sailed.
But again it is interesting to observe what will happen in the next few years. I hope my prediction is wrong.
After all, Five Eyes + EU + JK is pretty much THE non-China market out there. The others are not rich enough.