Surely evolving societal needs prompted these changes, but a side effect has been that designers now equate themselves with communicators. Certainly design can and often does communicate, but is design the same thing as communication? I don't think so.
In our experience, designers are no better at communicating than the average non-designer person, and many are worse. Designers are often introverts, craftspeople. Don't forget, we set type for a living.
Communications in a commercial setting, often known as the "corporate communications" function, usually includes advertising, public relations, and activities to support sales – brochures and the like. Typically corporate communications groups are comprised of writers, designers, and managers, who write, design, and manage the production of communications artifacts. Hardworking professionals spend a lot of time producing stuff under the guise of communicating.
Years ago I worked in a in-house corporate communications group that wrestled with the creative dynamics between writers and designers. Are we writing a headline for the picture, or creating a picture for the headline? For a team-building event, I designed a t-shirt which depicted divergent groups cross pollinating ideas. Even as an intern, I recognized how a basic truth is often missed.
Communication theory tells us that communications is a two way street. There is a sender and a recipient, but we often spend too much time on the broadcast. It's too easy to forget that communication is a process, not an event.
From the job interview to the board room, we focus too much on creating the perfect package, and not enough about whether it's signals versus noise – something Web 2.0 pioneers 37signals recognized early on. Communication is less about creating a perfect package abd delivering it to someone, and more about co-creation, learning, clarity.
Mastery of communications is likely a mystery that no one will get completely right (otherwise, all the marriage counselors would go out of business). Just remember what George Bernard Shaw suggested, that "the biggest mistake in communication is assuming it has occurred." Or, as the Beastie Boys might put it, get it together.