JonD
I suspect the internet has a bit to do with it. 
A lot easier, not to mention cost effective, nowadays to go to one place, say, NAMM, and then put up a bunch of videos.
While it's no substitute for the old-school, meet & greet type of demonstrations, one can certainly see why, from a business perspective, they might be phased out in favor of internet-based show and tell.
I think a good compromise would be to have regular webinars, where viewers worldwide can participate with questions and comments.
All excellent points, to which I would add...
People stopped coming to in-store clinics. Back when I did these kinds of workshops it was rare to have fewer than 50 people show up, 80-120 was the average, and some places did a lot more - Nashville could pull a couple hundred people easily, and my personal record was 300+ in San Antonio. I once did a 50-city tour for Panasonic spread over five countries...good times

Secondary markets (Columbus, Atlanta, Seattle, Dallas, etc.) were always the hottest.
These days, clinicians get excited if 20-30 people show up. It can be cost-effective to send someone to talk to 100 people, but not to talk to 20.