Advertising CPMs vary wildly between geographies and demographics. GP’s point is still valid: even if average global revenue is $10/mo/user, the average revenue of the group that would pay $10/mo is likely much higher.
And its likely a Pareto curve too.
So a 99th percentile user could be worth $1000 per month, 99.9th percentile worth $10000 per month, etc.
I imagine they would only take the risk to offer such a premium service when they can figure out how to get everyone to upload their payslips and bank account statements.