Of course, there is the maxim, "If it ain't broke, don't fix it."
Which would apply to items like 7710 Dura Ace Track Cranks. But, I'm sure that if the sales projections were good enough, Shimano could make some improvements to them. Notice how they change their pedals (even ever so slightly) every few years as well as their other components.
I think that handlebars (sprint and enduro) are an "Area of Opportunity" for our sport. For example, look at how many different TT bars we've seen in Kilo/500M rides over the years vs drop bars for sprint events, yet there are more drop bar sprint events than there are aerobar sprint events.
...this is why those who can make their own drop bars...make their own drop bars.
