My first trip to Mexico was in the mid ‘70’5 and have been there about 14 times. About five years ago, I was picked up at the airport in Monterey in a bullet proof car while visiting a factory. I will not go back. Sad really, because it can be a wonderful place.
For about 6 years I had to spend 1 week of every month in Guadalajara, on business. I never felt unsafe. Guadalajara was a nice town, I liked it and my Spanish was good enough to get around. It has been about 10 years now and I don’t think I would want to go now.