I see a lot of potential for the EU* to mandate an API that each company offering software or service subscriptions would have to implement. The goal being that every end user can have a central point where they could see all their subscriptions and cancel them at any point in time.
Most subscriptions here are paid via direct debit, which the app detects and groups under a "fixed expenses and subscriptions" category. If the charge is considered a subscription, they let you fill a generic form with some details about yourself (i.e. Address, Email, Phone, CustomerID ...) to request it be cancelled.
I reckon the bank(s) requires payment providers to handle this as part of the integration for recurrent debit authorizations.
* or any other powerful government body