Match of the century,... Covid 19 vs Homosapiens innate and adaptive immune systems,... winner take all.To your point, travel restrictions "worked" in New Zealand and Australia with tough measures and heavily controlled flights and quarantines. Covid got in anyway.
There are too many variables to control the spread of any virus due to the current status of global interaction and the interdependency we have created,... there is nowhere to run or hide,... unless of course you set up shop in the remotest of areas in the country of which you reside and become a full on Homesteader.
I suppose those who are full time Homesteaders are currently the safest from contracting the virus if they can avoid any contact with the outside world,... those lucky bastards, lol.
Tried the half-Homesteader thing 30 years ago while living in the remote area of Kenora, Northwest Ontario, it was extremely challenging and time consuming up and above of holding down a job,... couldn't imagine the effort needed to do it full time,... probably many 14 to 16 hour days.
Anyways,... I'll put my money on the Homosapiens finishing as the victors,... tried, tested and true for 200,000+ years,🏆