all parties agree that sufficient progress has been made, but this has been an obvious driver for quite some time.

See the last sentence in Swofford's quote below from July 2015 (David Teel article)

"If we’re going to do this,” Swofford said, “we need to do it in the right way from the beginning that gives us the opportunity to have long-term success, and that’s what we’re trying to do and time it in a way so the distribution can be good, if not great, coming out, if we go this route. The other alternative is larger rights fees (from ESPN).”

Of note, the annual costs for ESPN to produce the LHN and SECN are each less than the potential increase in rights fees ESPN would purportedly pay the ACC. And they've already built the capacity to distribute the ACCN.