Well, I don't know if they're going out or not, but I would hope that pearls of all sorts would always be appropriate. (I hope so, because I don't have gumball pearls, but I do have a vintage strand of what I'd describe as "flying saucer"-shaped faux pearls--I bought them because of their odd shape & I don't imagine that flying saucer pearls were ever a trend or that they ever will be, but I don't care because I have fun wearing them.) I do have a vintage turquoise gumball necklace, though. (I 've had it for a long time, so I've seen the gumball trend come & go, & while it's fun when it comes back in style, I keep wearing it because I really love turquoise.) Seems to me that pearl fans feel the same way about their assorted shapes & sizes of pearls, so I'd say keep wearing it & enjoying it no matter what the latest trend is!
Megan