From what I could gather from a quick google search Troy had about 9k main campus students in 2009. their first fbs year was 2001 and they made the decision to move to fbs before they left dII in the 90's. I can't find it but I'm guessing they had 5-6k students at that time. so you want to look at where they are now, but not where they were when they made the decision to move. that's not a far comparison. they were where we are now (actually not even) when they said we're going fbs. they just didn't let their fear outweigh their vision.
every school is going to be different. troy has a million campuses and if you look they said in 2009 they had over 30k students total if you count every campus and their online program, but in an apples to apples main campus to main campus comparison we aren't much different from when they made the decision.
multi-million dollar donors you say? and again... a million dollars is 1,000 alumni giving $1,000/each. heck, can I get 10,000 of you negros to give $100 dollars? there u go. done.