If you look at countries sorted by population [0] - and my justification for that is that communities don't scale up linearly - the US, Germany, Turkey and the UK are clear outliers.

And Australia isn't necessarily a target; Australia is basically importing a new population every century - ignoring natural population growth. That sort of growth requires a bit of thinking to justify; it isn't going to be for everyone. And if it is even achievable off a high starting population (without overwhelming infrastructure, etc) is questionable.

[0] https://en.wikipedia.org/wiki/List_of_countries_by_net_migra...