It may have never left, but it does not enjoy the popularity it once had ... It has been kept alive to some degree by swing dancing, but ask a 20 to 30 or even 40 something if they can do the 'jitterbug', or even know what it is, I think the vast majority will give a negative response ...
People you see doing it today are either in their 60's to 70's or are into swing dancing ...



I think any dance 'craze' needs more than one song to generate a lot of interest ... the 'Twist' started with one song but then there was a rash of others that followed ... Disco had many songs being played in clubs and on the radio ...
These dance styles also had exposure in the popular movies of the era, as did the 'jitterbug' ...