Maybe NCL can keep the prices high, but I have cruised cheaper than ever before this past year on Carnival. They do reduce prices to fill ships. If consumers aren't happy with an NCL price many will move along to other lines. Cruising is a commodity as well. Cruise lines will have more difficulty filling to capacity as flights remain high, as many are not going to cruise when it costs so much and is so difficult to get there and back home via flying.
As far as several comments on this not being a recession because the labor market is growing, that is just not going to work. Jobs are always trailing indicators of economic prosperity. With rampant inflation and rising interest rates, demand destruction has already begun. Jobs will not being growing much longer. No soft landings.
On the original question, I am waiting until 60 days, maybe only 30 days before travelling to buy a cruise. I got burned by NCL when I rebooked a cruise in January 2021 for March 2022, at $799 inside p/p. Less than 60 days before that cruise Club suite balconies were $699. For me I am waiting, I have the luxury to be very flexible.