I don't know if Medium deliberately chooses its superstars. Remember that the early adopters of a platform have a massive advantage over the newcomers. It's like compound interest. Lots of the current superstars started early when the platform was different and when there was less competition.

I also have a number of older readers. The younger crowd tends to read the self-help and start-up publications. So it's a question of which pool we're in, which depends largely on what we write about and where we're publishing it.