The reason is the weight, engine size and the price. $18,350 USD and 564lbs fully fueled isn't the type of bike I would want to ride off-road or leave in many parts of the 3rd world. As storysunfolding suggested above, a V-Strom would be less than 1/2 the price new (1/3 or less newly used!), and I'd take that myself. But on a basis of quality, performance, style and ultimate reliability, the BMW would be an excellent choice, it just depends on what you like.

I have always had a hard time with the look of the boxer engine.
Cool but not awesome.
Mike