I think the question is really "comparable". I agree that GaTech is a state school, not a private school. But in all other respects, it has not nearly been a "close option" if a student doesn't get into UGa, until maybe recently.
From GaTech's small (undergraduate) size, selective majors (heavy on the engineering side), and high academic standards, it hasn't been much of a "second choice" comparable state school option to UGa. A southern state comp to GaTech would be Auburn or Clemson, but both of those schools are larger and have more of a traditional undergrad-grad ratio. Those schools also offer more diversity of study than GaTech offers (at least at the undergrad level).
What I was referring to is a phenomenon in southern states with huge population growth. Look at the top 10 states (by population). Five are northern states, and when you add massive California and Texas, you have seven states that need to offer a lot of college education opportunities to a lot of people in a lot of locations. Some of these states (Pennsylvania, Ohio) have created massive "flagship" schools by concentrating the best educational opportunities in one location (Penn State, Ohio State). Other large states have a more diverse set of "state" universities, and while one state university may be "the best" (UC-Berkeley, UT-Austin), there are still a lot of other good state schools if you can't get into the flagship.
The three southern states that have recently boomed into the Top 10 population are Florida, Georgia, and North Carolina. The State of Florida had a long history of inequality for state schools (F$U was for women, FAMU was for blacks, even the funding was disproportionate until the 1990s). In short, UiF's "flagship" status was more than just a product of "excellence", it was created through a number of circumstances that became self-fulfilling prophecies.
GaTech is a great state school because of its mission, its standards, and its policies. UiF and UGa have benefited from being fake "flagship" schools in states with rapidly increasing populations. North Carolina allows the UNC name to be used in cities other than Chapel Hill. Florida and Georgia do not. UiF and UGa are just artificial "flagships" that have moved up the rankings due to fake "selectivity" stats.