The Atlanta suburbs get a lot of credit in the press, but the maps in the NY Times piece referenced in the linked Tweet show a dramatic Blue shift from 2016-2020.

Cohn et al. point out that overall Black turnout as a percentage of the vote declined this time around, and sure, that's true, if only because the number of White voters from both major parties was dramatically higher as well (and there are more White voters than African-American or Latinx voters in Georgia). But if you look at the county-by-county results, there are several rural or semi-rural counties where Trump still won, but he won by less. A few hundred votes here, and a few hundred votes there, and pretty soon -- in an election this close -- those little counties suddenly are no longer inconsequential. And it's Black voters in those areas who made the difference, I'm almost certain.

The map published by USA Today (scroll to bottom of page to How counties shifted from 2016) shows 2016-to-2020 differences in every county in the United States. Lee County, in southwest Georgia, for example, voted for Biden at a rate over 8% higher than for Clinton. Catoosa County, in northwest Georgia, went for Biden at a more than 4% higher clip.

I think the statewide GOTV efforts by Stacey Abrams and others are responsible for these modest gains in counties with lower populations than the heavy hitters in metro Atlanta, and they deserve credit for contributing to Biden's 14,000-vote lead in Georgia.