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