there have been rumours around of a DI ktm for a while now but i also reckon yamaha has one sitting somewhere too and the reason they are keeping the yz going is to keep their name in the game so that when/if any other brand drops a DI 2 stroke yamaha will be right there with them.
i would also like to see a comparison between a 2011 250 sx and 2011 250 yz. i am not completely convinced that the ktm would still be better than the yz in the overall package. yes they have a better engine but motocross isnt drag racing, and i think that is why yamaha is still selling so well.
as for the other brands not selling 2 strokes anymore you have to ask is the volume they are selling worth making and importing them? obviously for them its not and in the grand scheme of things the motorcycle department in a company like kawasaki/honda/suzuki is fairly small. that department is only responsible for a small amount of sales in those company's where as for ktm bikes are all they make so they have to diversify and offer as big a range as possible to make as many sales as possible. the japs are focusing on where the majority sales are and at the moment that is 4 stroke, if there is a change in the rules and/or 2 strokes make a huge comeback then i am pretty sure they will start making them again. in the meantime tho, they have put in a lot of R&D into the four strokes and if everyone stopped making them eventually everyone would have to ride the 4 strokes and they get the most out of their investment dollars. by suzuki not selling rm's anymore is sales that are not taking away from the rmz
