A third party app can just scrape catalogues, and then direct you to the platform’s website through an integrated browser to manage each account. They can push notifications when a subscription is about to be renewed just by remembering when you subscribed, and send reminders to cancel and subscribe to the next service in your queue.

The streaming companies won’t hide their catalogues because that’s how many people find what they want to watch through simple web searches, e.g. “Where to stream Barry” or “when does the new season of x come out?” The app could pull metadata from other sites for graphics and info like many already do.

It wouldn’t be as convenient as flipping a switch which would require proper API and probably login info, but seeing everything and managing it from one place would still help a lot.

I think a bigger danger would be platforms countering by requiring phone calls to cancel, or contracts, or slow-dripping content over months to keep you subscribed (some already do the latter.) IOW continuing to become more like cable.