Actually… if you look at past history, it generally hasn’t been stuff you expect to be popular. I mean, sure, most kids like Sesame Street, but “Tickle Me Elmo”? Who would have thought THAT would be the gotta-have-it gift?
Clearly NOT the manufacturers or retailers, who would have LOVED to have had enough of them available to sell to everyone that wanted one.
Whatever ends up being the runaway fad, right now it’s got some toy company executive lying awake at night thinking something along the lines of “Man, I pushed to have 20,000 of those things made; if we don’t sell at least 5,000 of them I’ll never work in this industry again.”