Actually they've got only around 3000 more students so whatever not a huge difference. That shouldn't be used by anybody as an excuse
I know "context" is a dirty word on message boards, but listen to the question and full answer. CPJ references the arms race in college football/athletics. When you have larger student body, that equals a larger alumni base, which can presumably fill a larger stadium. So the revenues that schools can derive from 80-100k stadium dwarfs middle-of-the-pack schools (like GT) when you start looking at multiplier effect of premium seating, seat license fees, concessions, parking, etc.
CPJ added that GT has held their own against Clemson during their tenure, but a lot has changed between 2008 and 2018. Clemson has successfully executed a plan that accentuates their advantages. His point is that GT can't take the Clemson blueprint and expect to have the same results, and he mentions the aspects that differentiate Georgia Tech:
“But I don't think that everybody has to try to do that to compete,” he said. “Everybody has to be positive with what they have. We've got a great school academically. We're in a great city. We have a lot of positives that we can sell rather than facilities sometimes."
CPJ is answering the question as a football coach and as an observer of college football, rather than a diehard fan. (It should be noted that the writer asking the question covers Clemson, so he's likely looking for affirmation that Clemson is doing it better than everyone else.)
I'm sure if CPJ has said that "There's no difference between GT and Clemson, and we should spend the same amount of money and recruit the same players," everyone would would think he's suffering from CTE (expect Fedora).
As an aside, one interesting thing about Clemson is that athletics does not get any money from student athletic fees. They still give free tickets, but priority goes to student IPTAY members, which is a great way to grease the pipeline for donations after graduation.
http://clemsontigers.com/sports/tickets/facilities/studenttickets/