Incorrect. Chongo94 has it - The FBS part is important in reading my comment. It is very limiting and bad for the program to limit yourself to only a few potential coaches, when very good can be found elsewhere. Also bad, when you are competing against bigger names for a hire among that very limited FBS HC only pool. I think TCU is a place that will do better finding the next up and comer, leave the 10 year established ones to A&M, UT, and USC - They do so well with it.
While mostly a nod to Keeler (FCS and Div III championships), there have been many coaches come from the FCS level. Some not so good, others great. That is part of the vetting or interview process.
But to be honest, I would not be against a great coordinator if they have shown they run their half of the team expertly and with great success. Success is not just wins/losses when evaluating a non-HC.