Interesting. I guess a big factor would be how widely used OpenStreetMap and TomTom (Apple's two primary data sources) are in a country.

OSM is widely used in EU for website map embeds (due to GDPR implications of Google Maps), and TomTom is very common for vehicle GPS in NZ.

If neither have wide usage in Mexico, I can see how Apple Maps wouldn't be very good, as they wouldn't have years worth of user-submitted corrections.