G5 HC is equal in prestige to an upper level P5 coordinator job. Considering he was a G5 position coach 2 years ago, that's incredible.It's Georgia Southern not UGA. I wouldn't expect some big name with a ton of coordinator or head coaching experience to end up being their head coach.
It depends on the G5 school. The old Georgia Southern head coach left to be the new Tulane head coach. That should tell you something about where they are in the G5 pecking order. Congratulations to coach Summers but I would think an offer to be DC at UGA, Michigan, etc. would have been a bigger opportunity for him.