I believe most of the commercial Android phones already have a regular task that resets permissions for unused apps to serve people who gave permissions accidentally or forgotten about them after setting them deliberately.
There is something that resets permissions, but only those that were granted and only if the app hasn't been used for a while. I'd find it annoying if I intentionally selected "always" for some given permission in an app I regularly use, only to have it occasionally reset itself. I already find the battery optimization notifications for apps I want running in the background annoying enough.
