Although the specialty networks have been money drains for ESPN, my guess is they are still willing to do them just to ensure a long-term relationship with the ACC. Look at what is happening with the Big Ten. They have their own network independent of ESPN and are now looking for another blockbuster TV deal. I am sure that as ESPN and Disney decide how to budget their rights deals, they would rather have a true partnership (with equity) with the ACC than overpay to lose money on a Big Ten deal.
Awful Announcing referenced the impatient ACC Athletic Directors. I am sure that is a factor, but the bigger factor is ESPN stopping the cord cutting. Once they have that figured out, then they can move onto creating the ACC Network.