Hmmm. Well, I personally won't go to someone else's country and label what they are doing to subsist as "crazy". I submit that when you see a family of 4 going down the road on a single scooter, you can't possibly have a clue as to the factors in their lives that put them there. It's hubris to assume the position to pass judgement on what they are doing.
Cozumel may be relatively prosperous, but that certainly does not mean that everyone there is participating in that prosperity. Have you been back in the residential areas away from the commercial zones? I have; I've even been invited into some of their houses. Seeing what I have seen, I won't criticize whatever they feel they have do to scrape by.
Peace,