Unfortunatley, travel insurance is about the only protection against all the disclaimers in the contracts. The cruiselines don't and can't take responsibility for air delays/cancellations. They don't run the airlines they have to use or own planes. The airline industry is notorious for delays and never guarantee arrival times for vacations, meetings or anything else. They also don't take responsibility for "Consequential damagers", like missing your cruise.
Lawyers run the world. They put in language to protect the companies that hire them, not the traveling public. Travel insurance can be just as riddled with exemptions and exclusions so you have to be very careful in selecting which coverage you purchase there as well. The cruiselines insurance would have provided you a future cruise credit for 80% of the cost of your cruise. Many outside providers offer 100% coverage and they do so in real $$$ back to your CC. You just have to shop carefully for the right policy with fewer exclusions and higher coverage.
You are not alone in believing when you book the cruise and the cruiseline's air you'd be protected. I hear it all the time. It's just not the case. Without insurance it doesn't matter who you bought your cruise or air from. There is no protection. I hope they will do something for you but don't expect they will. I'm an agent and your situation and other similar ones happen from time to time. It is very rare that I've seen a good outcome without the insurance.
Good luck with it, Neil