Earlier quoted context omitted.
At least when I was growing up, it was still the norm in the South/Texas. My parents would have never referred to the elderly in our neighborhood by their first names.
I also great up in Texas (30yo now). I was raised to always say sir/ma'am but for most adults that I knew well, we were on a first name basis. Deacons at church were usually on a first name basis (my parents volunteered a lot so I knew them all really well) but the one noticeable exception was the pastor and anyone in a teaching role. Teachers were always addressed by Mr/Mrs/Ms and this extended into Scouts as well.…
I also grew up in Texas and to this day I still tend to use sir/ma'am for most adults I don't know. Every now and then it seems to throw people off. People don't seem to expect to hear "Yes, sir" very often it seems.