Maybe I'm just not expressing myself well. All I meant by using jazz as a metaphor for DIY electronics is that there are still people learning their way around circuits, but it more of a niche pursuit, or boutique if you will, specialized and focused.
Likewise, jazz was once a living dialect, now it is (arguably) in some danger of becoming to some extent, a museum piece, or a re-enactment of its own historical self, instead of a new and ongoing extension. (not trying to start a flame war, I KNOW there are modern practitioners of jazz AND electronics who continue to break new ground, but I would argue they are the exceptions)
Electronics understanding is no longer as much a part of the general world, in which many people as a matter of course are absorbing the practice and the process, putting into use on a regular basis, and thereby amassing the skills and expereince needed to develop a solid general understanding, let alone a unique personal approach or method that leads to truly "incredible" gear, as you say. If anything, the IC engineer has taken over this position (or the programmer), as others have stated. But it is hard to fab a DIY 14-pin DIP IC in your garage...