Cozumel seems to have at least double to triple the number of taxis it really needs, no wonder they need more fares.
Last week after I was done with a dive I met up with my wife and the friends who had joined us for our trip. We were at a place not too far from where we were staying in Akumal, and my wife and friends took a taxi to get there. The plan was for them to snorkel and relax (while I nearly nodded off after a day of diving), eat some dinner, and then take a taxi back to Akumal. The taxi driver who brought my wife and friends said he would stay and take us back. We told him it would be hours (at least) before we were ready to return. He insisted. He sat around the entire time we were there, and when we were done with dinner, he took us back to Akumal. We realized it was a very smart move on his part. By waiting for us, he was guaranteed a fare. If he went somewhere else, he very well might not get a single fare the rest of the day. We talked with him on the way back and realized that he had taken a fare from Cancun to Akumal that morning and then sat in Akumal for many hours dong nothing until our group used him. By waiting for us, he managed to get in one more fare before returning home to Cancun. Those three fares probably constituted a very good day for him.