MMM:Hmm. That's an interesting observation. Certainly one sees a certain amount of restaurant turnover anywhere you go - it's the nature of the business. It would be interesting if Scubawife or anyone else with tourism/hospitality industry creds could substantiate that this can be chalked up to greater use of hotel meal plans.
While I'd rather poke needles in my eyes than stick to a diet of hotel buffets, I can understand why a family travelling with a bunch of kids of varying ages would not be anxious to scavange 3 meals a day in town for the hungry sparrows, I doubt that this type of traveller ever did head into town for their meals on any but the rarest of occasions.
I stay and eat in town and frequent places favoured by the locals, meaning they are east of 15th (and more likely, east of 30th and pushing 60th). They always seem full - but maybe because they aren't dependent on the AI or cruise crowd.
In Cozumel what's had an impact on businesses on the island has been the months right after Wilma with little of no tourist and then a lighter then usual high season. Factor in the loss of business with cost of repairs and the usual overhead and there will be restaurants and shops that just can't afford to stay in business. There always have been and always will be people who purchase meals plans. Those who stay in the southern AI's, for the most part were never going into town to eat anyway. Those who buy plans at hotels north of Fiesta Americana often do so just for the convenience of breakfast and lunch, which they would eat at the hotel anyway.
There are also a few restaurants that have been mentioned on this board and other Cozumel boards who's leases were up for renewal and the rent increases along with the needed repairs and no business made it impossible for them to continue. In any destination that relies heavily on tourism there are a handful of places that seem to have been around forever and you know they will be there every time you visit. There are others that turnover as leases are up.