Oh, it's definitely not generational.
I'm 23 and have never in my entire life called an adult by their first name (unless, for example, they were wearing a name badge that only said their first name andI had to reference them).
I would be mortified if my child didn't think the title default. However, if the adult corrects them with their first name, not a problem.
Heck, I met my fiance's grandmother and mother only last summer and still called them Ms X until told otherwise. Even when referring to other adults in their family I would say 'and that's what Mr Y went to the supermarket'.
I too can't stand being 'Spenguin' in business contexts. My estate agent e-mailed 'Spenguin' the other day. I just hit reply and annotated his e-mail with a 'By the way, we've never met and I could be 95 for all you know. So, 'Mrs Spenguin', if you wouldn't mind'
However, the title thing has its problems too - i.e. when you only now someone's first and last names. Do you use Ms or Mrs or Miss. God knows people get uppity about 'Ms'!