It is indeed strange. My feed shows quite a few people with interesting angles, but followings no bigger than mine.
And so many good writers spend a year or so, then leave.
It would be interesing to be a fly on the wall in the Medium decision room. Why do they keep propping up the top writers? It seems to me that if Medium is not yet making a profit, they need to change some things.
On another note, I suspect that when we put our tags to our articles, the algorithms really don't use those tags for much. What's your feeling on this?