It has been said many times before, but the truth is the Adventurers Club was not self sustaining. At best, it broke even, and typically made a loss. The removal of the PI turnstyle gave it a few extra years as a last ditch attempt, but it still didn't turn a profit. No business can operate like that, not even one that is supported by Disney. They really did give it every chance to succeed, and the closure was not taken lightly.
Despite how the fans loved it, the masses did not. They did not get the inside jokes, they did not understand the repetition, and they did not spend money in there. The regulars ended up just buying cokes and water, so the upshot was it failed.
I really don't think they are hurting now. The restaurants are packed, Disney are not operating any loss making enterprises, and the plans are in the works to move things on and upwards. Despite the internet folklore about DTD, I think they are in a good place with it internally. Better than they have been for years.