It dissapeared with the death of the first wave of prog, replaced by more sythesisers and computers, but is being single handedly reborn with the great high-energy rock fusion band Niacin.
Niacon formed in 1996, named after the B-3 vitamin and the B-3 Hammond organ, with the organ played by John Novello who name-drops Vanilla Fudge, Edgar Winter, Billy Preston, Greg Allman, Al Cooper, and Jan Hammer as his inspiration.
His co-pilot's have some pretty amazing music credentials:
The drummer is Dennis Chambers, a man who seems to have played with everyone: Steely Dan, Santana, Parliament, John McLaughlin, he's known for his ability to play 'in the pocket', which reads as it sounds when you think of funk.
Bass Guitar is supplied by Billy Sheehan, honored many times by Guitar Player Magazine. He's one-time member of glam-metal band Talas, played with Steve Vai for David Lee Roth, guested for metal-fusion band Planet-X and lots more