I think the argument about ports not being so quaint anymore can also be viewed as selfish - on the part of those who don't live there but still wish places were more rustic. So you want Cozumel and Grand Cayman to be like they used to be, just for you? What about the people who live there? Is it possible they might want a higher standard of living which cruise ship dollars bring, and not want to remain in their past, like a 40 year old travelogue film? Nobody twisted their arms.
Places evolve. They should not be expected to remain as they once were just to please the discerning tourist.