A story in the Oaxaca paper that caught my eye today was one about a Mexico Secretary of Tourism survey of foreign visitors which asked them to rate different ascpects of their Mexican tourism experience. The highest rated area was "hospitality" and the two lowest were limpieza, or basically "cleanliness," and "public transportation." I can certainly agree with any complaints regarding litter in Mexico, but I really don't understand how public transportation could be rated so low, especially since Mexican public transportation is so much better than that in the US (from where the majority of Mexico's tourists come from).
There are buses, vans, and collective taxis everywhere providing service to even the tiniest hamlets, and the long-distance buses, especially if you're a tourist who can afford the luxury lines, are really comfortable and reliable (they're light years ahead of Greyhound). Maybe tourists just don't like sharing a city bus seat with an occasional squawking rooster, but personally I think it adds some nice local color to the whole experience.