It's my opinion that Blackburn wasn't the first choice as AD because he already had too many "contacts" in the media and was seen as someone who might go rogue and do his own thing. Currie was a "clean slate" so to speak and one of the new breed of Athletic Directors. He had the right UT connections, but was far enough removed from the current leadership he was seen as a safe hire that was pragmatic. I have a contact that worked for him at K State and, again, he said "smooth talker and money making machine" (paraphrased) but Reid Sigmon was the one that was the one to keep an eye on.
For me, I think there was some baggage with Blackburn that only select few knew of. As to what, I won't even guess. But for some reason, the obvious choice as AD would have been him. However, someone blocked that from within and only a few knew why. Don't forget, he resigned from UTC this year without much of an explanation given. One doesn't get out of the game in their prime and after being mentioned for several top level positions other than UT for kicks.
There was something in the background we will never know with him not being selected. My opinion only.