Progressive Rock and Modal Jazz

Listening to some progressive rock recently. As with Zappa there are lengthy and yet interesting solos on one chord. Often the music stays in one key and develops rythmical riffs with increasing variations. The effect is often quite hypnotic. In the fusion category this effect / method is common as well and makes the two styles very similar. Not unsurprisingly really. Fusion proponents would be Steps Ahead and the Brecker Brothers. Zawinul often develops in this way. For me the skill is in making the solos interesting through rythmic variations and developing the licks. It is also common for the band to interact more than in mainstream jazz (this point may be more debatable). I would also argue that progressive rock and modal jazz are more European than American. American standards tend to be AABA in form and follow some very predictable (cliched?) patterns of choruses and single solos. The European tradition of clasical music tends to favour length and development through movements. Kenny Garrett's Wayne's Thang is very modal, 3 chords only. His version on YouTube is lengthy but keeps the interest because of the developments in the soloing as well as the hypnotic effect in the repetitions. Some people are derogetory about this form of soloing as it does not require the ability to modulate over frequent changes. However developing a good modal solo requires greater skill in phrasing to retain the interest.