Wasn’t the point that when those neighboring countries eventually open up, then the people that would have died will probably still end up dying and the numbers will look the same?

Bold claim Cotton, let's see if it works out... Joking aside, that is based upon the mostly discredited 'herd immunity' theory. It is not the case that someone who is in a vulnerable population is somehow doomed to die from this disease, and there are many different ways to mitigate the problems as countries respond to the ebb and flow of the different Covid waves. When the neighboring countries open up (and several of them have partially opened at times) they have more medical resources available to mitigate the effects and they are more prepared to revert to lockdown if necessary.