Good Product is not earning every dollar. Netflix recently announced they will start cancelling inactive subscriptions, Slack also carry out "Fair Billing Policy" to charge only active users in paid plans.

These companies can earn more money but they choose not to. This is because gaining users' trust & loyalty is more important than the monetary return.

Usage-based billing is a pricing model that can be both reasonable & flexible for users. Making the process transparent and credible will gain users' trust and loyalty.