I don’t think Barbie is all that popular for little girls here, but it enjoyed a brief boom of popularity among the junior/senior high set a few years ago. Barbie branded everything was pumped out of this store in Harajuku.
Fads move incredibly fast here. Unless it’s an evergreen character like Hello Kitty, a thing, a food, an entity, an actor or a band will cycle through within a year or two then vanish utterly. A limited edition item branded with a thing will cost $100 at a store, and a few months later you can pick up the whatever-it-is in at second hand mega chain Book Off Bazaar for $10.
But if a thing can reach a certain level of fame it can essentially coast forever, just based on nostalgia and familiarity.
I guess Barbie as fashion wasn’t kawaii enough to reach that level. Or it was the wrong kind of cute. Harajuku style is an insatiably ravenous beast, always cruising for the next thing to devour.