In a world where everything is expected to be free, you would need to have some amazing content to get anyone to subscribe to that idea.
It also creates the great financial divide where those who have the most, can make the most use.
There is little that gets better by using money as a motivator. It rarely brings out the best in people.
It only motivates those who don’t have any, it has little value to someone who is not short of it.
It would certainly get a large thumbs down from me.
I would rather go the hunger games route and get people to pay to boot people off a topic 
(kidding of course)