That’s mainly because they are versions of lighter and smaller road bikes. After all, that is what an original scrambler was; a road bike that people turned into dirt bikes with a few modifications so they could compete in weekend hare scrambles.
So, instead of BMW’s 1200cc R nineT Scrambler (pictured below), Oberdan has sketched a scrambler version of the lighter and smaller parallel twin F800 (pictured at the top of the page).
Surely that’s a much more authentic platform for a scrambler! BMW, take notice.
Oberdan has also produced some sketches of a Moto Guzzi V9 scrambler called the Desert Eagle.
There is actually a chance that Moto Guzzi could do this. At least they may make a scrambler accessory kit as they have done for the V7.