Calum's ppst effectively sums in up. I totally agree with this. There is almost a case for the "ground rules" being established for jazz between 1917 and 1970 and that this effectively produced the canvas upon which the jazz musicians of the last 30 years could experiment.
Picking up on "dominant" styles, I think it is probably correct that there has been no one voice who has really steered jazz in a particularl direction like louis, Bird or Coltrane but there is little need to do this. Any innovations in improvisation are incremental or a new voice may have a persuasive influence over their peers (probably the best example of this is Brad Mehldau who is amazingly influential with the jazz festival I attend each year being full of clone trios) but not offer anything too new. Without doubt, the jazz scene over the last 30 years is more varied, interesting and diverse than at any time in it's history.
I was curious to read Byas'd opinions about each of the decades. For me, the 80's rolled into the 90's and I felt it just showed an increasing degree of maturity with artists like bill Frisell and John Scofield who I was heavily into at the time. This was probably true if many other musicians as well although newer talent seemed to rise thick and fast whether it be Dave Douglas, Chris Potter, Joshua Redman, etc, etc. This process is still continuing thankfully. For me, there was a distinct chance around 1999/2000 as the Nu jazz fad kicked in and there seemed a period when the 21st century would see a flood of piano trios and "Scandi jazz." EST now seem pretty forgetable and I am pleased that much of this really tedious stuff is now far less popular. The "groove-based piano trio was a nightmare scenario and it is great to see the likes of Jason Moran and Vijay Iyer steering this instrument back to a proper path.
Picking up on the Frisell east/ West CD, I alwaus prefered the exceptional "Quartet" which is a curious post-modern take on the kind of jazz performed by Adrian Rollini in the 1920's, No doubt that this is jazz and still the best tecord BF has made under his own name in my opinion.