Perhaps, but that's not really relevant since the vast majority of people do not live in well functioning democracies.

Your post sounds like an assumption like "the people who live in war are a small minority so their position is an exception compared to humanity in general" when actually it's the opposite, the people who live in the well functioning first world democracies are a small minority so their position is an exception compared to humanity in general.

In that case leaders of USSR could use the same line to boast about their country.

In the 60s-70s life in USSR was better than in China, India, virtuall all of Africa and Latin America.

Yes, the leaders of USSR could do that and did just that, but I don't understand what this has got to do with any challenges to the original assertion that large quantities of people worldwide would be "very grateful to relocate to Georgia" - they would be. At the moment despite all the immigration restrictions that USA has implemented, the Green Card queue indicates a mass willingness to become residents of USA.

It's not about boasting, it's about whether USA can rely on people wanting to immigrate to ensure that places like Georgia stay sufficiently populated even if population naturally declines - and IMHO they can.

Depending on who you ask, percentage of people living in functioning democracies would be 0-10%.

Probably much higher for those living in the UK with its insane housing prices (10x the hours worked per square meter of Chicago!)