It may be twenty years old, but on what data do you base your conclusion that it is inaccurate? The fact that the design of motorcycles and the demographic of riders has changed does not invalidate anything Hurt said. It's simply unwarranted and unsupported speculation that something MUST have changed with respect to causality of accidents. Since Hurt concluded that most motorcycle accidents are caused by car driver inattention/failure to yield right-of-way you would be better off arguing that something in design of CARS or their drivers has invalidated the Hurt report, but that would be equally spurious without data to back it up.The hurt report is also 20-some years out of date and woefully innarcurate for modern stats.
I didn't see anything in that list of causes that does not conform perfectly with my unscientific observations over 30+ years of riding.