It's a definite uptick, in part because of the scholarship, and in part because of the population growth of the state. A lot of midwesterners migrated down here and historically they took education more seriously when it comes to spending money. That means the various high school systems which one were poor are now funded and decent (many are).
When I was a kid, spending money on just about anything was bad politically. My first elementary school had broken windows and no air conditioning, it really was a pretty rudimentary operation. We moved to suburban Atlanta and the county we lived in had quite a bit better funded schools, but they still were not good.
There is an historic basis to why B1G schools are good academically. The general quality of ACC schools is a bit harder to explain I think.