Supermotos are great bikes, but do not have wide appeal. Kawasaki, Suzuki, and Honda all dropped them because they did not sell well enough to be profitable. If you want one, just get a dual sport and build it. I never considered buying one, because none of them came with centerstands, and they use tubeless tires with tubes in them. I considered buying a used DR650 and building a supermoto out of it. It's a simple air cooled carbed bike, and an aftermarket centerstand is available for it. I might still do it, but I have bought and sold so many bikes lately I no longer have any extra cash.
I won't spend more on a bike than I think it's worth, but if it's a good deal, I don't seem to have a problem buying bikes I don't need.
2002 Vulcan 750, 2013 Royal Enfield B5
2001 XT225, 2009 Genuine Stella
1980 Puch moped