What has happened to the "Yorker"?

Don't fast bowlers learn (or want to learn) how to bowl a good old fashioned Yorker these days?  I can't see the benefit of bowling over after over of deliveries that a batsman does not even have to play at.  What a waste of time and energy!  Surely a few good toe crunchers would not only make the batsman jump a bit, but it may even result in a wicket.  I do acknowledge that this is a hard ball to bowl, but with practise, any fast bowler should be able to perfect this delivery, otherwise they should not be playing first class cricket.