Well my point was those students become alumni with money and you need a full cohort of graduates that "grew up" with a Georgia State football program to start filling the stadium. Most of my friends who went to Georgia State are still fans of other programs, but those that had a football team their whole undergraduate career will build momentum.
I believe further investing in a true identity for the program by having their own stadium will be a good thing. I personally would always rather go to BDS than the Georgia Dome for a GT game because of the atmosphere we have built at home.
This could be a threat, but to make a counterpoint to what I said above it doesn't seem like the commuter schools (USF, UCF, etc.) can seem to maintain momentum year over year like the traditional programs. Then again neither of those programs have their own facilities.