I agree , HD could have invested in sports bike engine R&D, they probably did on some small scale. But, my guess is that HD has lost money on the butt ugly V-Rod and the sexy Buells. Buells are cool, but like Jimmy2bad said he went with the Triumph Tiger, a bike that is hard to keep under 85 on the highway. In these economic times HD has to protect their niche market and manufacturing of big slow, comfortable cruisers that look like traditional bikes. Traditional looking motorcycles like ours.
I've never understood why Buell stuck with HD this long and visa versa, if he wanted to produce sports bikes. Well except for their once deep pockets.

Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. H. L. Mencken