Do you feel that a person becomes an Icon by what they know, how many gigs they get, how many chops they can throw at a set, or what?? Thats the point of the question, because alot of people can think they are an Icon but isnt considered one, hopefully people dont think its by AGE because that would be a misconception!!!
It is by age... because being considered and icon of legend is related to having been tried and proven. Chris Dave is a legend in the making if he continues his evolution. Legend/Icon status is all about having been proven by the top standards and surpassed them. Documented superiority to the established standards. Legends/Icons are often know by the fruit they bear and the company they keep.
Problem is these days that people don't adhere to any standards. The younger generations think they can rewrite a story they never read. Set new standards when they have not be proven by the established ones. The microwave mentality does not make legends.
I was re-reading the Louie Bellson cover issue of Modern Drummer and when asked about practice in his youth and it was 15 hrs a day on the weekends and 3 plus hrs a day on school days. You'll probably find similar stories of most folk we recognize as legends/icons today. Akira Jimbo practiced everyday all day for two straight years when he first started playing. The commitment is a good starting point for establishing a legend. Then comes the contribution.... What mark i sthe person making/leaving/has left? How did they change the game forever? Did they forge a new frontier?