Transition of Prog rock

you heard any of King Crimsons spontaneous stuff?    ..THRaKaTTaK comes to mind

This has always been a question that I have asked myself. I am a young prog rock fan that has grown up with parents that have been devoted fans of bands such as Yes and Genesis(gaberial years). I have always wonderd that in other forms of music during that time period have grown into forms of music that are very present in music scenes right now. Like how the Grateful Dead have basically created a entire genre of music that has followed up and continues to produce good music such as: THe string cheese incident, phish and widespread panic. I feel that with the complex instumental talents of bands such as Yes and Genesis that this would be able to push people to play this type of music.  I understand that bands like transatlantic, spocks beard and the flower kings have produced amazing music, yet i feel there should be a more broad base of a prog movement. Another question I propose is also , why didnt a band like Yes play shows were they would play solos and "jam" like the grateful dead? P.S. sorry for all of the grateful dead refrences, im not exactley a fan of there music, but more of there musicianship and there ablility to "jam" or produce such well played solos. thanks