Followers do not equal reads. Say you personally follow 500 people, are you going to read each one's articles on a daily basis? No. You won't.

As others have stated, each paying member only has $5.00 for Medium to parcel out to all of us writing. More writers, more articles, people read more, their $5.00 doesn't go as far. Medium is like a pie - the more people that try to eat the pie the smaller everyone's chunks are going to be.

If one person reads 50 articles a week their $5.00 goes quick, if someone reads 1 article a week and they read your article you will see a bigger take of their $5.00. At least that's how I understand it.

I have articles that have a larger amount of member read time that made less money, I would assume because those members read voraciously.

There is no cut and dried way to make each read = x amount of money.