Maybe you imagination is limited. China has done this precisely. They have kept the virus in check while limiting international travel and while being the world's factory. You open up when enough of your population is vaccinated.

I wonder why you feel that it is fine to say "too late" for this measure that obviously works. Do you also say too late to lockdowns, vaccine mandates, restaurant and schools closures, and mask requirements. If you don't, then maybe spend a moment thinking if your epidemic response is guided by your political allegiances

China is an authoritarian state that can almost anything it wants to do to limit the freedoms of its population. That same tactic won't work in (real) democratic countries, especially after 2 years of lockdowns.

New Zealand has a 14 day quarantine for international travelers: https://www.immigration.govt.nz/about-us/covid-19/border-clo...

Is New Zealand an authoritarian state?

A 14 day quarantine isn't a lockdown, even NZ is getting sloppy with virus measures. If the people there get tired of it there is nothing the government can do to stop them. In China you will get quarantined forcefully by the police state, and if you don't like it you can go to prison or get disappeared if you raise to big of a commotion.

New Zealand has cases, so what exactly is your point? The initial argument is that locking borders could prevent the spread of a highly contagious virus into a country. It cannot.

> China has done this precisely. They have kept the virus in check

According to their government...

> for this measure that obviously works

it obviously isn't since the various variations of the virus are spreading