an island with infrastructure that was built before anyone in the island had ever seen a cruise ship.
I'm pretty sure I disagree.
The electricity supply is very reliable (if eye-wateringly expensive) in all but the newest colonias. Water and sewer are reliable. Roads are pretty comparable to my local area in the US (Cozumel doesn't have frost heaves, but the end effect is similar in terms of surface quality). Phone (both landline and cellular) service is very good - cellular is much better than my local area in the US. We just switched ISP's because our cable company's speeds had dropped to unusable, but the DSL company is building out optical fiber rapidly. The airport is efficient and has free parking, and the ferry pier moves a lot of people. Every colonia has a park, there are playgrounds in every neighborhood including several that accommodate handicapped kids, there are multiple public libraries (including the one in the passenger jet), there are several public sports centers with tennis courts and pools (nicer than any I ever worked at in the US). There is public bus service that will get you almost anywhere. There are multiple good hospitals with good specialists. You can get many types of wonderful food delivered to your house night or day.
I'm pretty sure the island's infrastructure, by nearly every measure, has improved significantly since cruise ships began arriving. I wasn't there when ships began arriving and have no way of knowing whether cruises to the island have in balance been a good thing or a bad one. I do know that when my parents are at our house on the island the infrastructure there is better than that at their house about 2 miles from the town center of our little town in NH.
My NH home is not out in some backwater, and it's had time to develop infrastructure - Paul Revere cast the bell in the town clock and my house is older than the US Constitution. Some of our infrastructure was built before cruise ships existed. My parents live on a dirt road, can't get cable or broadband, have to have a generator due to frequent power outages, are on a well and septic, and my mobile phone doesn't work at their house (or at mine on Main Street, for that matter). Our town has no gas station. There is no food delivery of any type. Only a few towns in my entire state have any sort of bus service. If we need a neurosurgeon, dermatologist, or several other specialists we have to travel farther than the equivalent of the distance to Cancún to reach one, yet Cozumel has such specialists.