I think plenty of people will sail even with the "ludicrous" rules. I am one of them. Don't get me wrong, if I am on a cruise with 100% vaccinated people, I will agree that it is ludicrous to wear masks everywhere, but I will do it, and the joy of being on a cruise ship will so outweigh my discomfort, I won't even care anymore.
As much as some of us want the CDC rules to change, we know they won't, especially for the first cruises back. After a few months of successful sailings, who knows. But in July/Aug/Sep timeframe, those rules are etched in stone.
Staffing a ship and getting all your port agreements and stuff in place will take time. Hard to imagine how you speed that up. It will take as long as it takes.
The ONLY variables I see that has flexibility on how soon cruises can start is do a test cruise or don't, which has become the require vaccines or don't point of view, which has turned into the sail from FL or don't point of view. Seems the fastest way to set sail is to (temporarily) move operations out of FL, require vaccines, and cruise.
I'm not saying this is my preference...I choose to sail with my kids, and they are too young for vaccines. I'm just reading the tea leaves like everyone else. I think NCL pulls out of FL for a few months, and I think they will be very successful with their cruise start. I also think at some point, they return home to FL.
Others like Carnival and Royal, I saee them doing both vaccine cruises outside of FL and test cruises in the state.
DCL? No clue. My money is on test cruises out of FL but it's just a guessing game.