Yes. The rules were complicated, too. Children referring to adults and teachers with Mr./Ms. is a relic from what was once a more complicated set of rules about social hierarchy. Relative age, familiarity, and social status, both of the audience/listener and of the speaker relative to the referred person, were the main factors that determined the choice in how to refer to someone. The older, more socially distant, and socially superior they were to you, and the more formal the situation, the more likely you used the title. If the listener was socially distant or inferior to the party, you were more likely to refer to the party with a title. Using simply a last name without a title was also an option for a superior to an inferior. Given names were considered intimate to use alone, and reserved in private between family and close friends and sometimes close colleagues.
The change started in the '70s and it's not quite complete. More progressed in some regions than others. A couple decades ago, the manager at my first job was addressed as Mr. and it seemed quite natural to me at the time.