I do think it's a trend. An unfortunate one.

But a counter trend I am noticing is when I've gone to a new doctor (usually a specialist) there's a blank on the intake sheet to specify how I'd like to be addressed.

BTW, I'm American, 41, raised on the West Coast (and with plenty of manners, I might add. )

An akin disturbing trend is how some of my classmates, esp. the 18-22 undergrads as opposed to the older returning students, address the instructors as "Mr./Ms." rather than Professor. So far, I've never had a professor instruct me to do otherwise. And a friend of mine who is a professor of physical chemistry is really cheesed off by this trend as well.