I went to Mexico city with my family about 10 years ago and it didn't seem as you describe. I remember looking out our car window and seeing huge expanses of what seemed like shacks. Many of the road were wide with seemingly no lane markings, and people making their own lanes. We were at one such intersection, and got pulled over by a corrupt cop who was on foot. Supposedly we came too close to one the of people who constantly surround our car whever we stop, trying to sell us stuff. The cop took my dad's driver's license and demanded 1000 pesos to give it back. My dad negotiated it down to 200 pesos. We went to a hotel specifically chosen because it looked modern and had wifi. The pool was normal sized, but only had 1 foot of water, and it was green.