Kenors, in my corner of the country, I see way more, MORE, adventure riders, and dual sport riders than sportbike riders. I see about as much ADV/DS riders as I do H-D/cruiser/Sons Of Anarchy type riders. Sport bike riders I see less and less. And as I ride further away from population centers, I see even LESS if no sport bike riders at all. Yet I still encounter Cruiser, and ADV/DS riders.
I think this shift to adventure riding is just hitting its second wind. I just went to a local to me desert state park and visited the nearby town/watering hole. Mind you this park is surrounded by epic twisty roads. I saw what seemed like a ton of bikers stopping, having a drink, eating lunch, in a period of about 2 hours. Most of them were ADV/DS riders and cruisers. A handful were sportbikes. 10 years ago (I've been going there for that long), I remember seeing tons of sport-tourers and sportbikers stopping there. VFR's, CBR's, GSXR's, and Ducati's were everywhere. Now these have been replaced by Africa Twins, Suzuki DR650's, KTM's, and BMW GS's. I saw maybe one FJR1300. Meanwhile KTM 990's, 1190's, and 1290's were a dime a dozen!