I'm not sure it's down to Medium. They specifically say they want to see new writers being nominated, and in fact some nommers I've spoken have said that they actually seem to favour new over established.

If so, that's no bad thing, making sure that the trend towards same old, same old is actively counterbalanced by making sure newbie voices get a little leg-up to help them get started (and maintain their sub, natch - Medium ain't no charity).