Because people are using their stake different as well.

And why this big focus on the money ? Of course most people use Steemit to earn a bit but Steemit is not only about earning money. It seems like you are focussing on free and fast money and for this Steemit is the wrong place.

Questions like

"How to earn more tokens free in steemit?"
"How to earn free cryptocoin by completing task?"
"How to earn money online daily 10$ ?"
"Is steemit platfrom hard to make money?"
"How to earn free upvotes on steemit?"

show that you are not really in the platform itself but rather in the money. Maybe you should think about it.