On the issue of the $2,000-$2,500 premium cabin I meant airfare only: domestic first or international business. The only people who get cabins at that price on Seabourn that I have met are airline employees or retirees who get great deals on SOME Seabourn cruises (I guess if Seabourn is scrambling to fill up the ship.)
On the issue of TAs using consolidators for discounts on trans-ocean business seats, I don't know how that works with irrops and if any of the consolidators are doing things like using frequent flyer miles to buy tickets.
On Caribbean cruises with Seabourn I make my own airfare arrangements because I can usually do better if buying several months in advance than what Seabourn offers. As to the risk of my flight being late, I pick a cruise with a departure port on an island I like and arrive a couple of days early.