Interestingly enough sales of motorcycles amongst young people has been steadily declining for the last few decades. About the only people who buy larger motorcycles these days are old farts like me. Younger people, if they go for two wheeler at all, tend to choose electric scooters. Number of people passing their motorcycle test is declining while population is increasing.
The J.D. Power and Associates 2010 U.S. Motorcycle Competitive Information Study revealed that the average rider age increased from 40 in 2001 to 49 in 2010. I sincerely hope that this trend has slowed down, but doubt it has reversed. If it hasn't, the average riders age would be around 62 this year. 60-70 is an age where you're likely to either stop riding, or decide that your current bike will last until you do. The exceptions to that will not be able to carry the whole motorcycle industry alone.