I like to think that maybe someday there will no longer be such things as sculptors and composers and film-makers and playwrights and poets. There will only be artists.
— Tom Johnson
Johnson, a longtime music critic for the Village Voice, wrote that back in 1970-something, after being exposed to the then-burgeoning wave of multimedia artists. The impression he got was not of people who couldn't decide whether to work in film, music, sculpture or painting and so simply opted for "all of the above", but rather people who wanted to see what kinds of experiences could be produced by making different media share the same space.
I wonder what the Tom Johnson of 1970-something would have thought if he could have seen, say, today's video games. Those are multimedia experiences in a manner far more advanced than anyone of that period could have conceived of.
Actually — let me pop back a few steps. Consider the way a franchise is turned into not just an entertainment product but a slew of other concrete artifacts.
From what I've seen, the average anime release could result in:
a DVD/BD release of the series
a radio drama
light novel adaptations
light novel spinoffs
a manga adaptation of the main story
a manga side story
one or more soundtrack CDs
character figurines and other goods (wallscrolls, plushies, pillow covers)
and a video game adaptation (was wondering when I'd mention that?), which in turn could spawn that many more iterations of any of the above.
If that doesn't count as "multimedia", I'm not sure what would.
Now one of the possible comebacks to such a proposition would run something like this: "Yes, but the original (purist) definition of a 'multimedia artist' was one person working to combine multiple media!" That's a little like saying a film released by a studio isn't a "real" film — and it's not as if your more "conventional" multimedia production wouldn't consist of one artist directing a team of assistants, which is more or less the same situation that you have with any of the above.
And even when it's not — e.g., the soundtrack, which is ostensibly produced by someone who has never met the original creator — there's going to be at least some level of creative feedback between the people most directly responsible for the franchise and the people tasked with creating those individual pieces.
"Multimedia" isn't an obscurity. It's what most of us are doing right now on this here web thingy, and in a great many other places besides. In fact, one of the reasons I suspect I don't hear the term being used as much anymore is because it's almost completely redundant. You don't hear about "color TV" much either, you know. (And soon you won't hear much about "HD", except to talk about the quality of the source material and not the display itself.)