'Our modern transportation systems have effectively eliminated most of the barriers between human populations. All of our eggs are in one basket. If a highly lethal virus that will spread throughout an entire population and kill it arises, that basket will be dropped.'

This is a strong argument to change that situation. We have a communications system that lets us transmit data widely without needing personal contact. We could do some sorts of trade without a whole lot of risk, and minimise both the risk and the amount of trade for the rest.

It would be hard to do that effectively without a consensus among most of the world population, since people are so good at sneaking. So ideally over the next generation or so we'll develop a convincing case for dividing the world up into small breeding groups with strictly limited contact among groups, assuming the case actually is convincing.

At the moment the idea seems almost fantastical, as if we'd never put up with something like that. So we have a long way to go.