Wow! I was so surprised and so impressed by your question. I'm really glad you asked it. I've thought about this issue for over half of my life (that's more than 25 years) and I think that NPD is very common in Latin American culture in general and Mexican culture specifically. It is practically the norm, I think.
Like many descendants of Mexican immigrants I went on a journey of "finding my roots" that began 32 years ago. During that process I went to Mexico many, many times and stayed there for an extended period at least once. I traveled through more than half of it. I went to places outside of the tourist zones because I wanted to see the "real" Mexico. Heck, I even spent time in a Zapatista encampment in Chiapas.I went in search of long lost relatives and found them. I learned to read, write and speak Spanish fluently. I was married twice to a Mexican; one was highly educated and the other was a construction worker. I had a business where all of my clientele was either Mexican or Central American. I've been a teacher of ESL (English as a Second Language) and I've taught Spanish as a Second Language. I've had lots of Mexican and Mexican-American students over the years. My very first teaching job was even in Mexico. Throughout all of these experiences, my basic motivation was to find 1)what is a Mexican, culturally; 2) what is the best and worst in Mexican culture; and 3) is there anything of Mexican culture left in me? My conclusions here are based on anecdotal evidence, but it is a wide range of anecdotal evidence experienced in two countries, different contexts, and over a wide range of years with many, many Mexicans.
My conclusion is that Mexicans are very, very narcissistic. They are so narcissistic that they think this is the way humans are supposed to be and if you are not, then there is something wrong with you. This was a hard conclusion to come to because I wanted to believe otherwise. I wanted to believe the best. I wanted to believe that my family and the people I knew were the way they were because of "systemic racism" in the US or something else like that. But over and over again whether in business, education or just general daily living I found Mexicans to be abusive and with a huge sense of entitlement that had nothing to do with the US or its culture. These two characteristics manifest themselves in regular disregard for boundaries, both interpersonal boundaries and international boundaries. Within Mexican families the typical manner of interacting is everybody constantly interfering with everyone else with the eldest children, especially the male child bossing and bullying everyone else around. Emotional neglect is massive. I've seen this over and over again. The sense of entitlement manifests itself in the disregard for laws, especially traffic laws, immigration laws, you name it. And I rarely ever see a Mexican, or for that matter any Latino, express remorse about violating laws or boundaries. I've only seen two that even expressed any understanding of why violating laws could be a bad thing. It seems like for most of them, the only thing that matters is getting their way and getting what they want. I recall my first Mexican husband, the very educated one, telling me that his personal motto was "Primero yo, después yo, y finalmente yo." (Translation: Me first, then me, and finally me.) And he lived this motto, too. On another occasion he told me that he couldn't understand what was wrong with me because ever since we'd gotten married he'd been trying to change me and I just wouldn't change to suit him. My second Mexican husband once told me that what he wanted was for me to always put him first and at the center of my life all the time. My life should revolve around him 24/7! Imagine a country of 120 million people where most of the people are like this. There is a reason that narco-culture flourishes in Mexico. Mexican enablers always place the blame on the US because many American use drugs. But Mexicans play a huge role in this in that they see nothing immoral about selling drugs, since after all anything goes when it comes to making money. Frankly their narcissism disgusts me. Ironically enough, it's also their strength. It's what makes them come to the US illegally and set up businesses illegally and live in cultural enclaves that disregard US culture and laws. And over time they survive and have children here who become US citizens by birth but who, quite frequently, are just as narcissistic and unassimilated as their parents.
I have little patience for Mexican and Latin American narcissism and arrogance anymore and have decided that for whatever time I have left on this planet, the best thing for me is to get as far away from Mexican, Mexican-American, and Latino culture as possible. This is ironic as I am a Spanish teacher and work at a school filled with Mexicans and Mexican-Americans and I live in a Mexican/Mexican-American neighborhood. But, I'll think of a way. When I see non-Hispanic Americans making every effort to help Latin American immigrants stay here and making a big deal out of learning Spanish in order to communicate with them and providing every document for them in Spanish, I think to myself that these people do this because they really don't know the culture. They really don't understand what they are letting into their society.
As a teacher, I think the reason so many Mexican-American/Hispanic students do so poorly in school is that they are just too narcissistic to make the sacrifices that genuine learning requires. They, more often rather than less often, want to take the easy route and they regularly think everybody owes them something, whether that something is an easy grade, a free lunch, a US Visa, easy entry to college, pity, a job, free medical care, etc. All the hand-wringing in the world and extra programs to help Latino students in school will mean nothing until the fundamental narcissism of their cultures is recognized and dealt with.
The US is really going to be a messed up country in the future with the huge number of immigrants, legal and otherwise that are pouring into the country now (I'm writing in May 2019). These people bring so many problems with them. They bring physical health issues.They bring mental health issues. They are socially maladaptive and refuse to acculturate, much less assimilate to US culture. And their sense of entitlement knows few if any bounds at all. Witness the "Dreamers" and their supporters. Witness the economic migrants pretending to be political refugees. And all of this is the day-to-day manifestation of their personal and cultural narcissism.