Not exactly correct. Changes to VIFP, just like any other change a company would make, are done to maximize profit. That can be done by increases in revenue as well as decreases in expenses. If they think changes to the loyalty program will induce people will stay with or switch to Carnival, that increases revenue.
There are plenty of things that Carnival can do to enhance the loyalty program that would cost them little or no additional money. For example,
-guaranteeing a private table or booth in the MDR
-priority seating in popular venues like the piano bar or the comedy club
-one free photo per cruise