Is this for some special research or just something personal? I’ll speak from experience being currently in and from Mexico.
I would recommend you look into the “Cristeros” movement of Mexico which lit the Catholic faith on fire after it was being outlawed by the government (ONLY Catholics, no other faith.) Sad to see all those people who fought and died for the faith not even being in most schools or without the real details. There’s a recent Catholic Answers show on that with Patrick Madrid if you haven’t heard it. You could start with an overview here:
en.wikipedia.org/wiki/Cristero_War
Honestly I know another person who is also Mexican, went to the US and now he’s an atheist despite his apparent Catholic upbringing. I don’t know what but I’m convinced that our country went through some period were Catechesis became very poor which is why so many ill-formed “Catholics” pass on these falsehoods or lack of faith to their children. The upside of course is that now the Church and its members are doing what they can to promote the faith once more.
I know a lot of people who’ve never even read the Bible in its entirely. Heck,
I haven’t done so yet! Of course I was also a “Catholic in name” being in a American schools since Middle school so my faith consisted mostly of just going to Church and praying at night before going to bed. It’s thanks to things like Catholic Answers Live that I found my way (and realize just how little I knew).
As I heard on Catholic answers, it seems rather than live out the example, it seems people “inoculate” their kids against religion here. It all boilds down to mass on Sunday and you forget about God the rest of the week unless you have something to ask for. A lot of people are so disrespectful and of course you can bet their children learn it too (with the cellphone being the “almighty” because they’ll leave church to answer whatever call comes their way).
The problem seems to be in part because of “catholics” seeing the faith just as a mere tradition to follow, never delving into what it really entails or what they’re receiving when going to communion.
The trivialization of religious objects to the point where they seem like mere ornaments is also likely to blame (a cross or rosary no longer a clear sign of a truly devout Catholic as many seem to wear them as any another accessory).
A recent “trend” is a company that sells stickers/bracelets/etc with a cartoony Virgin Mary with a very banal “prayer” accompanying the image. The text on the virgin roughly translates to: “little virgin, please take care of my great car.” With the “prayer” talking about allowing one to put up with traffic and being able to successfully bribe an officer.
lh4.ggpht.com/_A98OSmGV-hc/ScTumCurnqI/AAAAAAAAANo/myepQOyYqvw/s400/APT0089.jpg
In the end it seems to boil down to this: the average Mexican is
VERY EGOCENTRIC. It’s all about “me” and everything else is second. God is meant to be #1 so you can see how He’s quickly pushed aside for “more important” things (but He’s the one they immediately rush to when in need).