For example, Monterrey and Nuevo León in general has always been fairly calm and it is a major hub globally for automotive, power electronics, and machining.
Most of the rise of criminalization in Mexico can be tied to the economic crises of the 1994-96 (peso crisis), 2001-03 (factories moving from Mexico to China), 2008-09 (collapse of automotive industry in the US, and then COVID (8.3% GDP contraction - one of the worst globally).
Whenever the Mexican economy recovers, criminality tends to recede.
Source: Mexican.
In fact, Mexico could be growing even faster if organized crime is brought under control.
The fundamentals in Mexico are fairly strong (relatively high median household income, access to the largest market globally, decent enough social indicators) and good governance can carry it forward dramatically.
That said, we in the US could help much further by actually sanctioning Cartel organizations en masse, instead of doing it haphazardly as we are today. Similar economic warfare forced the Italian and Japanese governments to drastically crack down on organized crime in the 90s and 2010s respectively.
Cartel violence is present even is large urban centers, ask anybody who runs a moderately successful business.
Or could it be that whenever criminality recedes, the Mexican economy recovers?
And this does make sense - if you don't have a job, the cartel's offer is fairly competitive.
Also, those areas that tend to be the most violent are also part of the now largely defunct Maquiladora belt.
[0] - https://www.macrotrends.net/global-metrics/countries/MEX/nor...
[1] - https://www.macrotrends.net/global-metrics/countries/MEX/mex...
Maybe things will change with the Mexican elections this year but I doubt it. The front runner is a protege of the current populist president.