Before it was the Coticule craze that seems to be quieting down. People want higher finish on their edges.

There was the Escher craze, now we do not talk much about those anymore but they are still very sought after. Prices are steady and not going down as far as I can tell.
There was the J-Nats craze. Still a lot of people use them and buy, but with price hikes it is hard to afford a full size stone. People still get them but I so not see many posts about new J-Nats anymore.

Now we see all kinds of naturals pop up a lot not very good for razors, but many shavers are looking for cheaper natural hone so money is being made out of people that do not know how to grade hones and know no better.

For razors, I think Japanese straights are still on the rise, Filarmonica craze seems to be quieting down. Not sure about WB not following the trends, I think only the choppers still command high prices, might be wrong though.