You got it right about land-based tipping escalating - but got it wrong about the same thing on ships.
Just 15 years ago the average recommended tip was $18 per person per day. Now the industry average is $10. That's nearly a 50% reduction !!
In the same 15 years, the average cruise fare has dropped more than 50%. Forgetting that those dollars were worth much more 15 years ago than they are today, cruising and tipping are a much better bargain - and far far less expensive than they were just a few years ago. How many other things in your life are like that?????